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780 recordsATP
Adenosine triphosphate, the cell's main short-term energy carrier.
Glycolysis · Glycolysis (human)
The ten-step cytosolic pathway that splits one glucose into two pyruvate, with a net gain of 2 ATP and 2 NADH.
Cellular Respiration · Cellular respiration
How cells transfer energy from fuel molecules into ATP, often using oxygen in the final electron-accepting step.
DNA
A double-stranded molecule whose sequence stores and passes on hereditary information in most cells.
Mitochondrion
An organelle that supports energy conversion and many other cellular processes.
Photosynthesis
The capture of light energy and transfer of carbon from carbon dioxide into organic molecules by plants, algae, and some bacteria.
1,3-Bisphosphoglycerate · 1,3BPG
An acyl-phosphate with high phosphoryl-transfer potential, formed when G3P is oxidized.
10-Formyltetrahydrofolate · 10-formyl-THF
A folate cofactor that donates one-carbon units during purine-ring synthesis.
2-Oxoglutarate · α-KG
A five-carbon citric acid cycle intermediate also called alpha-ketoglutarate.
2-Oxoglutarate dehydrogenase complex · EC 1.2.4.2
Oxidatively decarboxylates 2-oxoglutarate to succinyl-CoA.
2-Phosphoglycerate · 2PG
3-Phosphoglycerate with the phosphate moved to carbon 2.
3-Hydroxy-3-methylglutaryl-CoA · HMG-CoA
An intermediate formed from acetyl-CoA in the mevalonate pathway.
3-Hydroxy-3-methylglutaryl-CoA lyase · EC 4.1.3.4
Produces acetoacetate and acetyl-CoA from HMG-CoA in leucine catabolism.
3-Hydroxyacyl-ACP
The first reduced intermediate in fatty-acid synthase elongation.
3-Ketoacyl-ACP
The condensation product in one fatty-acid synthase elongation round.
3-Ketoacyl-CoA
The oxidized intermediate cleaved by thiolase during beta-oxidation.
3-Methylcrotonyl-CoA
A leucine-catabolism intermediate formed by oxidation of isovaleryl-CoA.
3-Methylcrotonyl-CoA carboxylase · EC 6.4.1.4
Biotin-dependent enzyme in leucine catabolism.
3-Phosphoglycerate · 3PG
The product of the first ATP-generating step.
3′ Untranslated region (3′ UTR) · 3′ untranslated region (3′ UTR)
The transcribed portion of an mRNA after its coding sequence that can influence RNA stability, location, and translation.
4E-BP1 (EIF4EBP1) · eukaryotic translation initiation factor 4E binding protein 1
A translation-regulating protein. mTORC1-dependent phosphorylation can reduce 4E-BP1 binding to eIF4E, helping control translation initiation.
5-Aminoimidazole ribonucleotide · AIR
The first purine intermediate containing a closed imidazole ring.
5-Aminoimidazole-4-carboxamide ribonucleotide · AICAR
An intermediate also used in cellular energy sensing after purine synthesis.
5-Phosphoribosyl 1-pyrophosphate · PRPP
An activated ribose phosphate used to assemble purine nucleotides and to enter pyrimidine synthesis.
5-Phosphoribosylamine · PRA
The first committed intermediate of de novo purine-ring synthesis on the ribose scaffold.
5′ Untranslated region (5′ UTR) · 5′ untranslated region (5′ UTR)
The transcribed portion of an mRNA before its coding sequence; it is present in the mature message but is not part of the main protein-coding region.
6-Phosphogluconate · 6PG
The hydrolyzed lactone intermediate oxidized to ribulose 5-phosphate.
6-Phosphogluconate dehydrogenase · EC 1.1.1.44
Oxidatively decarboxylates 6-phosphogluconate to ribulose 5-phosphate and NADPH.
6-Phosphoglucono-1,5-lactone · 6PGL
The first oxidized intermediate of the pentose phosphate pathway.
6-Phosphogluconolactonase · EC 3.1.1.31
Hydrolyzes 6-phosphogluconolactone to 6-phosphogluconate.
ACAA2 · NCBI Gene 10449
ACAA2 contributes to Acetyl-CoA acyltransferase 2.
ACACA · NCBI Gene 31
ACACA contributes to Acetyl-CoA carboxylase.
ACADM · acyl-CoA dehydrogenase medium chain
Encodes medium-chain acyl-CoA dehydrogenase for mitochondrial fatty-acid oxidation.
ACADVL · NCBI Gene 37
ACADVL contributes to Very-long-chain acyl-CoA dehydrogenase.
Acetoacetate
A four-carbon ketone body and one endpoint of leucine catabolism.
Acetoacetyl-CoA
A four-carbon thioester formed from two acetyl-CoA molecules on the route to mevalonate.
Acetyl-CoA
A two-carbon acetyl donor that connects carbohydrate, lipid, amino-acid, and energy metabolism.
Acetyl-CoA acyltransferase 2 · EC 2.3.1.16
Cleaves 3-ketoacyl-CoA with CoA, releasing acetyl-CoA and a shortened acyl-CoA.
Acetyl-CoA carboxylase · EC 6.4.1.2
Biotin-dependent enzyme that makes malonyl-CoA, the committed precursor for fatty-acid synthesis.
ACLY · NCBI Gene 47
ACLY contributes to ATP-citrate lyase.
ACO2 · NCBI Gene 50
ACO2 contributes to Aconitase 2.
Aconitase 2 · EC 4.2.1.3
Reversibly isomerizes citrate to isocitrate through cis-aconitate.
Acquired Drug resistance · Acquired drug resistance
A reduction in drug response that develops as cells or tumors adapt under treatment pressure.
Action Potential · Action potential
A rapid, regenerative change in membrane voltage that carries signals along excitable cells such as neurons.
Active Membrane Transport
Transport that moves substances against a gradient by coupling movement to an energy source.
Adaptive Immune Response
Antigen-specific B- and T-cell responses that can form immunological memory.
ADCY5 · adenylate cyclase 5
Encodes one membrane adenylyl cyclase isoform that synthesizes cAMP from ATP in response to regulatory inputs including Gαs.
Adenosine monophosphate · AMP
A purine nucleotide formed from IMP and used in RNA, energy transfer, and signaling.
Adenylosuccinate lyase · EC 4.3.2.2
Releases fumarate from SAICAR during purine-ring assembly.
Adenylyl Cyclase 5 (ADCY5) · adenylate cyclase 5
A membrane enzyme isoform that converts ATP to cyclic AMP. ADCY5 is one example of the adenylyl cyclases regulated by G-protein and other cellular inputs.
Adipocyte
Adipocytes store or use energy and send signals that help coordinate whole-body metabolism.
Adipose Tissue metabolism · Adipose tissue metabolism
Adipose tissue stores triglycerides after feeding and releases fatty acids during energy demand.
ADP
Adenosine diphosphate, formed when ATP gives up a phosphate and recharged to ATP in the payoff phase.
ADSL · NCBI Gene 158
ADSL contributes to Adenylosuccinate lyase.
ADSS1 · NCBI Gene 159
ADSS1 contributes to AMP branch enzymes.
Adult Hemoglobin A · hemoglobin alpha2-beta2 tetramer
Hemoglobin A is the main adult hemoglobin, assembled from two alpha-globin and two beta-globin subunits, each bound to heme.
AGL · NCBI Gene 178
AGL contributes to Glycogen debranching enzyme.
AGO2 · argonaute RISC catalytic component 2
Encodes AGO2, a catalytic RNA-binding protein that can guide target cleavage within RNA-induced silencing complexes.
AGO2 · argonaute RISC catalytic component 2
The catalytic Argonaute component of many siRNA-loaded RISC complexes. Cleavage depends on guide-target pairing, RNA accessibility, and the relevant cellular context.
AICAR transformylase · EC 2.1.2.3
Transfers a second one-carbon unit to AICAR.
AIR carboxylase · EC 4.1.1.21
Adds carbon dioxide to AIR during purine biosynthesis.
AIR synthetase · EC 6.3.3.1
Closes the imidazole ring of an FGAM intermediate.
AKT1 · AKT serine/threonine kinase 1
Encodes AKT1, a kinase activated downstream of PI3K-generated PIP3 that regulates diverse cellular targets.
AKT1 · AKT serine/threonine kinase 1
A serine/threonine kinase recruited to the membrane by PIP3. AKT1 is phosphorylated by more than one kinase and regulates many targets involved in growth, survival, and metabolism.
AKT2 · AKT serine/threonine kinase 2
Encodes AKT2, an AKT isoform with a prominent role in insulin-regulated glucose and lipid metabolism.
AKT2 · AKT serine/threonine kinase 2
An AKT kinase isoform recruited into phosphoinositide signaling. AKT2 has a prominent role in insulin-stimulated glucose transport in muscle and adipose tissue, while AKT isoform contributions overlap and depend on cellular context.
Alanine · L-alanine
Alanine is a compact amino acid used to build proteins. Its small, nonpolar side chain can fit into many protein structures.
ALDOA · NCBI Gene 226
ALDOA contributes to Fructose-bisphosphate aldolase.
ALDOB · NCBI Gene 229
ALDOB contributes to Fructose-bisphosphate aldolase.
ALDOC · NCBI Gene 230
ALDOC contributes to Fructose-bisphosphate aldolase.
Allele
One of the alternative DNA sequence forms found at a particular genetic locus.
Allergy Test panel (components unspecified) · Allergy testing panel
A generic allergy test panel; the allergens and analytes it covers were not specified.
Allosteric Regulation · Allosteric regulation
Control of a protein's activity when a molecule binds at a site other than its main working site.
Amino Acids · Protein-building amino-acid set
Meet the 20 standard amino acids that build most proteins, plus selenocysteine and pyrrolysine, two rare amino acids that some organisms encode directly.
Ammonium · NH4+
The protonated form of ammonia; a nitrogen source used by carbamoyl-phosphate synthetase I.
AMP branch enzymes · EC 6.3.4.4
Converts IMP through adenylosuccinate to AMP; the displayed step groups the branch reactions.
Anti-dsDNA Antibodies · Antibodies to double-stranded DNA
Autoantibodies against double-stranded DNA; testing is used to help diagnose lupus.
Anti-HBc (total) · Total antibody to hepatitis B core antigen
Total antibody to hepatitis B core antigen, indicating past or current HBV infection; vaccination does not produce it.
Anti-HBe · Antibody to hepatitis B e antigen
Antibody to hepatitis B e antigen, usually associated with reduced viral replication.
Anti-HBs · Antibody to hepatitis B surface antigen
Antibody to hepatitis B surface antigen, indicating immunity after recovery or vaccination.
Anti-HCV · Antibody to hepatitis C virus
Antibody to hepatitis C virus, indicating current or past exposure; it does not by itself establish current infection.
Antibiotic
A medicine that kills or inhibits susceptible bacteria; antibiotics do not treat viral infections.
Antibody
An antigen-binding immunoglobulin made by B-lineage cells that can neutralize targets or recruit other immune mechanisms.
Antigen
A molecular structure that can be specifically recognized by immune receptors or antibodies.
Antigen Presentation · Antigen presentation
Display of peptide fragments on major histocompatibility complex molecules for recognition by T cells.
Antimicrobial Resistance · Antimicrobial resistance
A heritable or acquired microbial property that reduces susceptibility to an antimicrobial agent.
Antineutrophil Cytoplasmic antibodies (ANCA) · Antineutrophil cytoplasmic antibodies
Autoantibodies against neutrophil proteins; testing helps evaluate autoimmune vasculitis and related systemic autoimmune conditions.
Antinuclear Antibodies (ANA) · Antinuclear antibodies
Autoantibodies that bind nuclear components; common in lupus but also found in some healthy people.
Antisense Oligonucleotides · Antisense oligonucleotides
Short synthetic nucleic-acid strands designed to bind a selected RNA sequence and alter its processing or use.
Apoptosis · Programmed cell death
A regulated form of cell death that helps remove cells during development and in response to certain stresses.
Apoptosis Signaling · Apoptosis signaling
The regulated pathways cells use to initiate and execute programmed cell death.
Archaea
A domain of cellular life distinct from Bacteria and Eukarya, with diverse metabolisms and habitats.
ARG1 · NCBI Gene 383
ARG1 contributes to Arginase 1.
Arginase 1 · EC 3.5.3.1
Hydrolyzes arginine to urea and ornithine, closing the cycle.
Arginine · Arg
A nitrogen-rich amino acid that is cleaved to urea and ornithine in the urea cycle.
Argininosuccinate
The urea-cycle intermediate cleaved to arginine and fumarate.
Argininosuccinate lyase · EC 4.3.2.1
Cleaves argininosuccinate to arginine and fumarate.
Argininosuccinate synthase · EC 6.3.4.5
Adds aspartate to citrulline in an ATP-dependent reaction.
ASL · NCBI Gene 435
ASL contributes to Argininosuccinate lyase.
Asparagine · L-asparagine
Asparagine is a polar amino acid whose side chain can form hydrogen bonds with water and other parts of a protein.
Aspartate · Asp
An amino acid that contributes the second nitrogen atom of urea.
ASS1 · NCBI Gene 445
ASS1 contributes to Argininosuccinate synthase.
Astrocyte
Astrocytes help maintain the chemical environment around neurons and interact with blood vessels and synapses.
ATIC · NCBI Gene 471
ATIC contributes to IMP cyclohydrolase.
ATP synthase (complex V) · EC 7.1.2.2
Uses the proton-motive force across the inner mitochondrial membrane to synthesize ATP.
ATP-citrate lyase · EC 2.3.3.8
Uses ATP and coenzyme A to cleave cytosolic citrate into acetyl-CoA and oxaloacetate.
ATP5F1A · NCBI Gene 498
ATP5F1A contributes to ATP synthase (complex V).
Autoimmune Liver disease · Autoimmune liver diseases (category)
A broad category of liver conditions driven by immune attack, including autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis.
Autoimmune Liver disease antibody panel (components unspecified) · Autoantibody panel for autoimmune liver disease
A panel of autoantibody tests used in evaluating autoimmune liver disease; the specific components were not specified.
B Cell · B cell
A lymphocyte whose activated descendants can secrete antibodies and form memory cells.
Bacteria
One of the three domains of cellular life, comprising prokaryotic organisms with extensive metabolic and ecological diversity.
Bacterial Conjugation · Bacterial conjugation
Contact-associated transfer of DNA between bacterial cells, often involving a conjugative plasmid.
Bacterial Transduction · Bacterial transduction
Transfer of bacterial DNA between cells by a bacteriophage.
Bacterial Transformation · Bacterial transformation
Uptake and incorporation of extracellular DNA by a competent bacterial cell.
Basophil
Basophils are rare circulating granulocytes that can participate in allergic and type 2 immune responses.
BCAT1 · NCBI Gene 586
BCAT1 contributes to Branched-chain amino-acid aminotransferase.
BCAT2 · NCBI Gene 587
BCAT2 contributes to Branched-chain amino-acid aminotransferase.
BCKDHA · NCBI Gene 593
BCKDHA contributes to Branched-chain alpha-keto-acid dehydrogenase complex.
BCKDHB · NCBI Gene 594
BCKDHB contributes to Branched-chain alpha-keto-acid dehydrogenase complex.
Beta Thalassemia · HBB-related reduced beta-globin production
A group of inherited blood disorders in which HBB variants reduce or prevent beta-globin production, limiting functional hemoglobin and healthy red blood cells.
Beta-globin · hemoglobin subunit beta
Beta-globin pairs with alpha-globin and heme to form hemoglobin, the oxygen-binding protein in red blood cells.
Biased Agonism · Biased agonism
A ligand-dependent preference for some receptor signaling routes over others.
Bicarbonate · HCO3−
Dissolved inorganic carbon used in carboxylation reactions.
Biogeochemical Cycles · Biogeochemical cycles
Transfers and transformations of elements among organisms and environmental reservoirs.
Blood Cell
Blood cells develop from hematopoietic stem cells and include cells that transport gases, defend against infection, or support clotting.
BRAF · B-Raf proto-oncogene, serine/threonine kinase
Encodes a RAF-family kinase that can activate MEK proteins in the RAS–RAF–MEK–ERK signaling module.
BRAF · B-Raf proto-oncogene, serine/threonine kinase
A RAF-family kinase that relays signals from RAS toward MEK1 and MEK2. Its activity depends on cellular context and regulatory interactions.
BRAF V600E and MAPK signaling
A recurrent BRAF variant that can drive MAPK-pathway signaling and create a context-dependent drug target.
Brain Metabolism · Brain metabolism
The brain requires a continuous energy supply and can adapt fuel use during prolonged fasting.
Branched-chain acyl-CoA intermediates
A grouped label for the distinct acyl-CoA intermediates formed by branched-chain keto-acid dehydrogenase.
Branched-chain alpha-keto acids
The three corresponding keto acids formed by transamination of leucine, isoleucine, and valine.
Branched-chain alpha-keto-acid dehydrogenase complex · EC 1.2.4.4
Irreversibly oxidatively decarboxylates the branched-chain keto acids.
Branched-chain Amino acid catabolism · Branched-chain amino acid catabolism in human metabolism
Leucine, isoleucine, and valine share transamination and oxidative decarboxylation steps, then diverge. Leucine is ketogenic; isoleucine is both ketogenic and glucogenic; valine is glucogenic. Their carbon enters metabolism as acetyl-CoA, acetoacetate, or succinyl-CoA.
Branched-chain amino acids
Leucine, isoleucine, and valine, shown together at their shared first catabolic steps.
Branched-chain amino-acid aminotransferase · EC 2.6.1.42
Transfers the amino group from leucine, isoleucine, and valine to alpha-ketoglutarate.
CAD · NCBI Gene 790
CAD contributes to CAD multifunctional enzyme.
CAD multifunctional enzyme · EC 6.3.5.5
Carries out the first three reactions of de novo pyrimidine synthesis: carbamoyl phosphate formation, aspartate addition, and ring closure.
Calvin Cycle · Calvin cycle
A chloroplast-stroma cycle that uses ATP and NADPH to incorporate carbon dioxide into triose phosphate and regenerate its carbon acceptor.
Carbamoyl aspartate · Carbamoyl-Asp
The first committed pyrimidine intermediate formed from carbamoyl phosphate and aspartate.
Carbamoyl phosphate · Carbamoyl-P
An activated carbamoyl donor made in mitochondria for the urea cycle.
Carbamoyl-phosphate synthetase I · EC 6.3.4.16
Mitochondrial enzyme that combines ammonia and bicarbonate using two ATP; activated by N-acetylglutamate.
Carbohydrate Biosynthesis · Carbohydrate biosynthesis
The conversion of triose phosphates from carbon fixation into sucrose, starch, and other carbohydrates.
Carbon Cycle · Carbon cycle
The movement of carbon among atmospheric, aquatic, geological, and living reservoirs through biological and physical processes.
Carbon dioxide · CO2
A carbon atom released during oxidative decarboxylation reactions.
Carbon dioxide · CO₂
A small carbon-containing molecule fixed into organic compounds by photosynthesis and released by many respiratory and decomposition processes.
Carbon Fixation · Carbon fixation
Incorporation of inorganic carbon, such as CO₂, into organic molecules by an organism.
Carboxyaminoimidazole ribonucleotide · CAIR
A carboxylated intermediate in purine-ring assembly.
Cardiac Muscle Cell
Cardiac muscle cells contract in a coordinated way to pump blood through the heart.
Carnitine palmitoyltransferase 1A · EC 2.3.1.21
Transfers long-chain acyl groups to carnitine to support mitochondrial import.
CDKN1A · cyclin dependent kinase inhibitor 1A
A p53-responsive gene that encodes p21, a protein involved in slowing cell-cycle progression.
Cell Cycle · Cell cycle
The ordered stages a cell follows as it grows and divides.
Cell Signaling · Cell signaling
How cells detect information and convert it into changes in behavior, chemistry, or gene activity.
Cell Wall · Cell wall
A supportive outer layer found in plants, fungi, and many microorganisms; animal cells do not have cell walls.
Cellular Metabolism · Cellular metabolism
The connected reactions cells use to obtain energy and build the molecules they need.
Chemiosmosis
The use of an ion gradient across a membrane to power a cellular process such as ATP synthesis.
Chlorophyll
A family of light-absorbing pigments that transfers excitation energy to photosynthetic reaction centers.
Chloroplast
A plant and algal organelle that houses photosynthetic membranes and carbon-assimilation machinery.
Chloroplast Stroma · Chloroplast stroma
The aqueous compartment inside the chloroplast envelope and outside the thylakoid lumen.
Cholangiocyte
Cholangiocytes line bile ducts and modify the fluid that flows through them.
Cholesterol
A membrane sterol and precursor for steroid hormones, bile acids, and vitamin D.
Cholesterol Biosynthesis · Cholesterol biosynthesis in human metabolism
Cells build cholesterol from acetyl-CoA through the mevalonate pathway. Acetyl units form HMG-CoA, HMG-CoA reductase makes mevalonate, and activated isoprenes assemble into squalene, lanosterol, and finally cholesterol.
Cholesterol Homeostasis · Cholesterol homeostasis
The balance of cholesterol synthesis, uptake, transport, and removal across tissues.
Chondrocyte
Chondrocytes make and maintain the specialized matrix of cartilage.
Chromatin
DNA packaged with proteins and other molecules that organize chromosomes and influence access to genetic information.
Chromosome
A DNA molecule together with associated proteins and other components that organize and transmit genetic information.
CI-MPR (IGF2R) · insulin like growth factor 2 receptor
A multifunctional receptor that binds mannose-6-phosphate-tagged cargo and participates in trafficking selected lysosomal enzymes. This is one route among several, and uptake depends on cargo and cell context.
Citrate
A six-carbon citric acid cycle intermediate formed from acetyl-CoA and oxaloacetate.
Citrate synthase · EC 2.3.3.1
Condenses acetyl-CoA and oxaloacetate to form citrate.
Citric Acid cycle · Citric acid cycle in human metabolism
The citric acid cycle oxidizes the acetyl group of acetyl-CoA to two carbon dioxide molecules while regenerating oxaloacetate. Each turn yields three NADH, one FADH2, and one GTP (or ATP), which feed biosynthesis and oxidative phosphorylation.
Citrulline
A urea-cycle intermediate exported from the mitochondrial matrix to the cytosol.
Class IA PI3K · Class IA phosphoinositide 3-kinase heterodimer
A regulatory p85 subunit and catalytic p110 subunit form a lipid kinase complex. When activated, it can convert PIP2 to PIP3, helping recruit AKT and other signaling proteins to the membrane.
Coding Sequence (CDS) · Coding sequence (CDS)
The part of a transcript annotated as specifying a protein sequence, from its translation start through its termination codon.
Coenzyme A · CoA
A carrier of activated acyl groups.
Concentration Gradients · Concentration gradients
Differences in a molecule's concentration across space that can drive diffusion and help power transport.
Connective Tissue Cell
Connective-tissue cells help make, maintain, or remodel the matrix that supports tissues.
Covalent KRAS inhibition
A drug strategy that forms a covalent bond with a mutant cysteine in KRAS G12C to inhibit selected KRAS states.
COX4I1 · NCBI Gene 1327
COX4I1 contributes to Cytochrome c oxidase.
CPS1 · NCBI Gene 1373
CPS1 contributes to Carbamoyl-phosphate synthetase I.
CPT1A · NCBI Gene 1374
CPT1A contributes to Carnitine palmitoyltransferase 1A.
CRISPR Gene editing · CRISPR gene editing
A programmable system adapted from microbial defense to target selected DNA sequences.
Crossing Over · Crossing over
Exchange of corresponding DNA segments between nonsister chromatids of homologous chromosomes during meiosis.
Crossing The blood–brain barrier · Crossing the blood–brain barrier
A delivery challenge because many therapeutic proteins and other large molecules do not readily enter the brain from blood.
CS · NCBI Gene 1431
CS contributes to Citrate synthase.
Cyanobacteria
A group of bacteria that perform oxygenic photosynthesis and contribute to aquatic and terrestrial primary production.
Cyclic AMP
A small intracellular second messenger made by adenylyl cyclases downstream of selected receptors.
CYP51A1 · NCBI Gene 1595
CYP51A1 contributes to Sterol-processing enzymes.
Cysteine · L-cysteine
Cysteine is a sulfur-containing amino acid. Its reactive thiol group can form a covalent link with another cysteine.
Cytidine triphosphate · CTP
A pyrimidine triphosphate used in RNA synthesis and lipid biosynthesis.
Cytochrome c (oxidized) · cyt c (Fe3+)
A mobile heme electron carrier on the outer face of the inner mitochondrial membrane.
Cytochrome c (reduced) · cyt c (Fe2+)
The one-electron-reduced form of cytochrome c.
Cytochrome c oxidase · EC 7.1.1.9
Transfers electrons to oxygen, reducing it to water and contributing to the proton gradient.
Cytoplasm
The contents of a cell outside the nucleus, including cytosol and many cellular structures.
Cytoskeleton
A network of protein filaments that supports cell shape, movement, organization, and intracellular transport.
Cytosol
The aqueous phase of the cytoplasm outside membrane-enclosed organelles.
Cytotoxic T cell
A CD8⁺ T lymphocyte that can kill target cells displaying recognized peptide–MHC class I complexes.
DBT · dihydrolipoamide branched chain transacylase E2 subunit
Encodes the E2 subunit of the branched-chain ketoacid dehydrogenase complex.
Delivering Therapeutic oligonucleotides · Delivering therapeutic oligonucleotides
Getting an antisense or siRNA drug into the right tissue, cell, and intracellular compartment.
Dendritic Cell
Dendritic cells collect and process material, then can show antigen fragments to T cells.
DHCR24 · NCBI Gene 1718
DHCR24 contributes to Sterol-processing enzymes.
DHCR7 · NCBI Gene 1717
DHCR7 contributes to Sterol-processing enzymes.
DHODH · NCBI Gene 1723
DHODH contributes to Dihydroorotate dehydrogenase.
Dihydroorotate · DHO
A cyclic intermediate oxidized to orotate in the mitochondrial inner membrane.
Dihydroorotate dehydrogenase · EC 1.3.5.2
Oxidizes dihydroorotate to orotate at the mitochondrial inner membrane.
Dihydroxyacetone phosphate · DHAP
A three-carbon ketose phosphate released by aldolase and converted to glyceraldehyde 3-phosphate.
Dimethylallyl diphosphate · DMAPP
The isomer of IPP that primes prenyl-chain synthesis.
DLAT · NCBI Gene 1737
DLAT contributes to Pyruvate dehydrogenase complex.
DLD · NCBI Gene 1738
DLD contributes to 2-Oxoglutarate dehydrogenase complex.
DLST · NCBI Gene 1743
DLST contributes to 2-Oxoglutarate dehydrogenase complex.
DNA Base pair · DNA base pair
Two complementary DNA bases joined across opposite strands: adenine pairs with thymine, and cytosine with guanine.
DNA Repair · DNA repair
Cellular systems that detect and fix many forms of DNA damage.
DNA Replication · DNA replication
How a cell copies its DNA before division.
DNA-encoded Libraries · DNA-encoded libraries
Collections of small molecules tagged with DNA barcodes that record each compound's identity during pooled binding selections.
Drug Selectivity · Drug selectivity
How preferentially a drug affects one target or pathway compared with other biological targets.
Duchenne Muscular dystrophy · Duchenne muscular dystrophy
A genetic muscle disease caused by DMD variants that disrupt production of functional dystrophin.
DUSP6 · dual specificity phosphatase 6
Encodes a phosphatase that can dephosphorylate ERK proteins and participate in MAPK pathway feedback.
DUSP6 · dual specificity phosphatase 6
A dual-specificity phosphatase that can remove activating phosphates from ERK and contribute to feedback regulation.
Ebola Disease · Ebola disease
A severe illness caused by infection with an orthoebolavirus; Ebola disease is not caused by every virus in the Filoviridae family.
EBV IgA antibody (antigen unspecified) · IgA-class antibody to an Epstein-Barr virus antigen
An IgA-class antibody test against Epstein-Barr virus; the source list does not specify which viral antigen is measured.
ECHS1 · NCBI Gene 1892
ECHS1 contributes to Enoyl-CoA hydratase.
EGF · epidermal growth factor
Encodes a precursor that is processed to release epidermal growth factor, a ligand that binds EGFR.
EGF · epidermal growth factor
A growth-factor ligand produced by processing a larger precursor. EGF can bind EGFR and trigger receptor signaling.
EGFR · epidermal growth factor receptor
Encodes a cell-surface receptor tyrosine kinase that can activate RAS–MAPK and PI3K–AKT signaling.
EGFR · epidermal growth factor receptor
EGFR is a receptor tyrosine kinase. Ligand binding can promote receptor pairing and phosphorylation, creating docking sites for adaptors that connect to RAS–RAF–MEK–ERK and PI3K–AKT signaling. Which branches dominate depends on receptor abundance, trafficking, ligand, and cell state.
EGFR–HER2 Heterodimer · EGFR–ERBB2 receptor tyrosine kinase heterodimer
A representative ERBB receptor pair. Ligand-bound EGFR can pair with HER2; HER2 has no established soluble ligand of its own and can feed both MAPK and PI3K signaling through receptor-associated complexes.
EIF4EBP1 · eukaryotic translation initiation factor 4E binding protein 1
Encodes 4E-BP1, a translation regulator whose phosphorylation by mTORC1 can release eIF4E to support translation initiation.
Electron Carriers · Electron carriers
Small molecules such as NADH that collect and deliver electrons between metabolic reactions.
Endocrine Cell
Endocrine cells release hormones or other signals that can coordinate activities in distant cells and organs.
Endocytosis
A family of processes that internalize extracellular material or plasma-membrane components into membrane-bound vesicles.
Endoplasmic Reticulum · Endoplasmic reticulum
A membrane network involved in protein production and processing, lipid synthesis, and calcium storage.
Endosomal Escape · Endosomal escape
The release of internalized therapeutic molecules from endosomes into the cytoplasm or other site where their target resides.
Endosome
A membrane-bound sorting compartment that receives endocytosed cargo and routes it for recycling, further transport, or degradation.
Endothelial Cell
Endothelial cells form the inner lining of blood and lymphatic vessels.
Enhancer
A regulatory DNA region that can raise transcription by binding regulatory proteins and communicating with a promoter.
ENO1 · NCBI Gene 2023
ENO1 contributes to Enolase.
ENO2 · NCBI Gene 2026
ENO2 contributes to Enolase.
ENO3 · NCBI Gene 2027
ENO3 contributes to Enolase.
Enolase · EC 4.2.1.11
Mg2+-dependent dehydration of 2-phosphoglycerate to phosphoenolpyruvate.
Enoyl-CoA hydratase · EC 4.2.1.17
Adds water across the double bond of trans-2-enoyl-CoA.
Enterocyte
Enterocytes absorb nutrients from the inside of the intestine.
Enteroendocrine Cell
Enteroendocrine cells sense nutrients and other cues and release hormones that help coordinate digestion and metabolism.
Enzyme Replacement therapy · Enzyme replacement therapy
Treatment with a manufactured enzyme to replace or supplement activity that is deficient in a particular disease.
Enzymes
Biological catalysts that speed reactions; most known enzymes are proteins, while some RNA molecules also catalyze reactions.
Eosinophil
Eosinophils are granulocytes involved in responses to some parasites and in allergic inflammation.
Ependymal Cell
Ependymal cells line fluid-filled spaces in the brain and spinal cord.
Epidemiology
Study of how health events are distributed in populations and what factors influence them.
Epithelial Cell
Epithelial cells form sheets that cover surfaces and line many organs and tubes in the body.
Epstein-Barr virus · Human gammaherpesvirus 4
A very common herpesvirus that spreads mainly through saliva and stays in the body for life after infection.
Epstein-Barr Virus infection · Infection with Epstein-Barr virus (human gammaherpesvirus 4)
Infection with a very common herpesvirus that can cause infectious mononucleosis and then persists silently for life.
ERBB2 · erb-b2 receptor tyrosine kinase 2
Encodes HER2, a receptor tyrosine kinase that can pair with other ERBB-family receptors and signal into growth-control networks.
ERBB3 · erb-b2 receptor tyrosine kinase 3
Encodes an ERBB-family receptor with impaired intrinsic kinase activity that signals through partnering receptors and adaptor proteins.
ERK1 (MAPK3) · mitogen-activated protein kinase 3
A MAP kinase activated by MEK1 or MEK2. ERK1 can phosphorylate many targets; its effects depend on the cell and signal context.
ERK2 (MAPK1) · mitogen-activated protein kinase 1
A MAP kinase activated by MEK1 or MEK2. ERK2 can phosphorylate many targets and move into the nucleus after some signals.
Erythrocyte
An erythrocyte, or red blood cell, carries oxygen through the blood using hemoglobin.
Erythrose 4-phosphate · E4P
A four-carbon sugar phosphate used in biosynthetic pathways.
Escherichia coli
A diverse bacterial species that includes harmless strains as well as strains associated with disease.
Exon
A gene segment retained in a mature RNA after processing; an exon may contain coding sequence, untranslated sequence, or both.
Exon Skipping · Exon skipping
A splicing strategy that omits a selected exon from pre-mRNA, sometimes restoring the reading frame of a disease-associated transcript.
FAD
Oxidized flavin adenine dinucleotide, an electron acceptor in the TCA cycle and beta-oxidation.
FADH2
Reduced flavin adenine dinucleotide that carries electrons to the respiratory chain.
Farnesyl diphosphate · FPP
A 15-carbon isoprenoid intermediate used to make squalene and other products.
Farnesyl diphosphate synthase · EC 2.5.1.10
Combines isoprenoid units to make farnesyl diphosphate.
FASN · NCBI Gene 2194
FASN contributes to Fatty acid synthase.
Fatty acid synthase · EC 2.3.1.85
Multifunctional enzyme that repeatedly extends an acyl chain to palmitate using malonyl units and NADPH.
Fatty Acid synthesis · Fatty acid synthesis in human metabolism
In the fed state, cytosolic acetyl-CoA is converted to malonyl-CoA. Fatty acid synthase uses an acetyl primer, repeated malonyl additions, and NADPH to build palmitate, which can then be elongated or desaturated.
Fatty Acid β-oxidation · Fatty acid β-oxidation in human metabolism
Mitochondrial beta-oxidation repeatedly oxidizes, hydrates, oxidizes again, and cleaves fatty acyl-CoA. Each complete turn shortens the chain by two carbons and yields acetyl-CoA, NADH, and electrons that reach ubiquinone.
Fatty-acid Oxidation · Fatty-acid oxidation
The stepwise breakdown of fatty acids that supplies acetyl-CoA and electron carriers to other pathways.
FBP1 · NCBI Gene 2203
FBP1 contributes to Fructose-1,6-bisphosphatase.
FDFT1 · NCBI Gene 2222
FDFT1 contributes to Squalene synthase.
FDPS · NCBI Gene 2224
FDPS contributes to Farnesyl diphosphate synthase.
Fed And fasting states · Fed and fasting states
Coordinated changes in hormones and fuel use that help the body respond to eating and time without food.
Feedback In signaling · Feedback in signaling
Signals can feed back to strengthen, weaken, or reshape the pathway that produced them.
Feedback Inhibition · Feedback inhibition
A control pattern in which a later product reduces activity earlier in the process that makes it.
FGAM synthetase · EC 6.3.5.3
Uses glutamine to add a nitrogen atom during purine-ring assembly.
FH · NCBI Gene 2271
FH contributes to Fumarase.
Fibroblast
Fibroblasts make and remodel much of the extracellular matrix that supports tissues.
Formamidoimidazole carboxamide ribonucleotide · FAICAR
The last open-ring intermediate before inosine monophosphate is formed.
Formylglycinamide ribonucleotide · FGAR
A purine intermediate after transfer of a one-carbon unit from formyl-THF.
Formylglycinamidine ribonucleotide · FGAM
A purine intermediate formed when glutamine donates nitrogen to FGAR.
FOXO1 · forkhead box O1
Encodes a transcription factor regulated by insulin signaling and involved in tissue-specific gene programs.
FOXO1 · forkhead box O1
A transcription factor whose activity and localization can be regulated by AKT-dependent phosphorylation. In hepatocytes, insulin-linked FOXO1 regulation can change expression of genes involved in glucose production; this is one part of broader liver control.
Fructose 1,6-bisphosphate · F1,6BP
A six-carbon sugar with phosphates on carbons 1 and 6, ready to be split in half.
Fructose 6-phosphate · F6P
The ketose isomer of glucose 6-phosphate.
Fructose-1,6-bisphosphatase · EC 3.1.3.11
Hydrolyzes fructose 1,6-bisphosphate; a bypass of the irreversible PFK-1 step.
Fructose-bisphosphate aldolase · EC 4.1.2.13
Splits fructose 1,6-bisphosphate into two three-carbon phosphates. Human aldolases are class I enzymes that work through a Schiff-base intermediate.
Fumarase · EC 4.2.1.2
Reversibly hydrates fumarate to malate.
Fumarate
A four-carbon citric acid cycle intermediate and product of argininosuccinate cleavage.
G6PC · NCBI Gene 2538
G6PC contributes to Glucose-6-phosphatase.
G6PC1 · glucose-6-phosphatase catalytic subunit 1
Encodes the catalytic component of the glucose-6-phosphatase system.
G6PD · NCBI Gene 2539
G6PD contributes to Glucose-6-phosphate dehydrogenase.
G6PD Deficiency · Glucose-6-phosphate dehydrogenase deficiency
Variants that reduce G6PD activity can leave red blood cells less able to manage oxidative stress.
GAPDH · NCBI Gene 2597
GAPDH contributes to Glyceraldehyde-3-phosphate dehydrogenase.
GAR synthetase · EC 6.3.4.13
Adds glycine to phosphoribosylamine during purine-ring assembly.
GAR transformylase · EC 2.1.2.2
Transfers a one-carbon unit from 10-formyl-THF to GAR.
GART · NCBI Gene 2618
GART contributes to AIR synthetase.
Gaucher Disease · Gaucher disease
An inherited lysosomal disorder associated with reduced glucocerebrosidase activity and accumulation of its lipid substrate.
GBE1 · NCBI Gene 2632
GBE1 contributes to Glycogen branching enzyme.
GCK · NCBI Gene 2645
GCK contributes to Hexokinase.
GDP
Guanosine diphosphate; it accepts a phosphate in the succinyl-CoA synthetase reaction.
Gene
A region of genetic material used to produce a functional RNA; some genes also provide instructions for a protein.
Gene Expression · Gene expression
The regulated use of information in a gene to make functional RNA or, for protein-coding genes, protein.
Gene Regulation · Gene regulation
How cells control when, where, and how strongly genes are used.
Gene Variants · Gene variants
DNA sequence differences that can have many different effects.
Genetic Variation · Genetic variation
Differences in genetic material among individuals or populations, generated and reshaped by multiple processes.
Genomics
Study of an organism's genome, including its sequence, organization, variation, and change over time.
Genotype
The genetic-variant or allele combination considered for an individual or locus.
Geranyl diphosphate · GPP
A ten-carbon prenyl intermediate formed from DMAPP and IPP.
Germ Cell
Germ cells give rise to gametes and pass genetic information to the next generation.
Glial Cell
Glial cells are nervous-system cells that support, protect, insulate, or regulate the environment around neurons.
GLP-1 Receptor signaling · GLP-1 receptor signaling
Signaling through a class B GPCR activated by glucagon-like peptide 1 and related agonists.
Gluconeogenesis · Gluconeogenesis in human metabolism
Gluconeogenesis makes glucose from lactate, glycerol, and glucogenic amino acids, mainly in liver and kidney. It bypasses the three irreversible glycolysis reactions and shares the other reversible steps in the opposite direction.
Glucose · Glc
A six-carbon sugar and the starting fuel for glycolysis.
Glucose 1-phosphate · G1P
A phosphorylated glucose intermediate shared by glycogen turnover and sugar metabolism.
Glucose 6-phosphate · G6P
Glucose carrying a phosphate on carbon 6. The charged phosphate keeps it inside the cell.
Glucose-6-phosphatase · EC 3.1.3.9
Hydrolyzes glucose 6-phosphate in the endoplasmic reticulum of glucose-exporting tissues.
Glucose-6-phosphate dehydrogenase · EC 1.1.1.49
Catalyzes the first, rate-controlling oxidation of the pentose phosphate pathway.
Glucose-6-phosphate Dehydrogenase · G6PD · EC 1.1.1.49
G6PD catalyzes the first reaction of the oxidative pentose phosphate pathway, reducing NADP+ to NADPH.
Glucose-6-phosphate isomerase · EC 5.3.1.9
Interconverts glucose 6-phosphate and fructose 6-phosphate.
GLUT4 Glucose uptake · GLUT4 glucose uptake
Insulin and muscle contraction can move GLUT4 transporters to the surface of muscle and adipose cells.
Glutamate · Glu
An amino acid that commonly receives or donates amino groups in nitrogen metabolism.
Glutamine · Gln
An amino acid that donates nitrogen in nucleotide synthesis and other biosynthetic reactions.
Glutamine phosphoribosylpyrophosphate amidotransferase · EC 2.4.2.14
Catalyzes the first committed step of de novo purine synthesis.
Glutathione Peroxidase 1 · GPX1 · cytosolic glutathione peroxidase
GPX1 uses reduced glutathione to reduce hydrogen peroxide and other peroxides.
Glutathione Reductase · Glutathione-disulfide reductase · GSR
Glutathione reductase uses NADPH to convert oxidized glutathione (GSSG) back to reduced glutathione (GSH).
Glyceraldehyde 3-phosphate · G3P
The three-carbon aldose phosphate that enters the payoff phase. Each glucose yields two.
Glyceraldehyde-3-phosphate dehydrogenase · EC 1.2.1.12
Oxidizes G3P with NAD+ and adds inorganic phosphate through a catalytic-cysteine thioester intermediate.
Glycinamide ribonucleotide · GAR
A purine-pathway intermediate after glycine is added to the ribose scaffold.
Glycine · Gly
A small amino acid that contributes two atoms to the purine ring.
Glycogen
A branched glucose polymer used for short-term glucose storage, especially in liver and skeletal muscle.
Glycogen branching enzyme · EC 2.4.1.18
Creates alpha-1,6 branches in glycogen.
Glycogen debranching enzyme · EC 3.2.1.33
Transfers short glucose chains and hydrolyzes alpha-1,6 branch points during glycogen breakdown.
Glycogen Metabolism · Glycogen metabolism in human metabolism
Glycogen metabolism stores glucose when it is plentiful and mobilizes the branched polymer between meals or during muscle work. Liver glycogen can support blood glucose; muscle glycogen is used locally.
Glycogen phosphorylase · EC 2.4.1.1
Releases glucose 1-phosphate from non-reducing ends of glycogen.
Glycogen Storage and breakdown · Glycogen storage and breakdown
How cells build glycogen from glucose and break it down when glucose or energy is needed.
Glycogen Storage disease type I · Von Gierke disease spectrum
GSD Ia involves G6PC1; GSD Ib involves SLC37A4. Both impair the final release of glucose from glucose 6-phosphate.
Glycogen synthase · EC 2.4.1.11
Extends the alpha-1,4-linked glycogen chain using UDP-glucose.
GMP branch enzymes · EC 6.3.5.2
Converts IMP through XMP to GMP; the displayed step groups the branch reactions.
GMPS · NCBI Gene 8833
GMPS contributes to GMP branch enzymes.
GNAS · GNAS complex locus
A complex human locus that encodes Gαs among several products; Gαs relays signals from selected GPCRs to adenylyl cyclases.
Goblet Cell
Goblet cells secrete mucus that helps protect and lubricate epithelial surfaces.
Golgi Apparatus · Golgi apparatus
A membrane-bound sorting and processing center that receives cargo from the ER and sends it to destinations.
GPCR Agonists and antagonists · GPCR agonists and antagonists
Ligands that increase or prevent a G-protein-coupled receptor's signaling response.
GPCR Signaling · GPCR signaling
How G-protein-coupled receptors convert outside signals into intracellular changes.
GPI · NCBI Gene 2821
GPI contributes to Glucose-6-phosphate isomerase.
GPX1 · glutathione peroxidase 1
Encodes a cytosolic selenoprotein that uses glutathione to reduce hydrogen peroxide and other peroxides.
Graded Potential · Graded potential
A local change in membrane voltage whose size varies with the input and that can spread passively over a limited distance.
Granulocyte
Granulocytes are white blood cells with prominent cytoplasmic granules, including neutrophils, eosinophils, and basophils.
GRB2 · growth factor receptor bound protein 2
Encodes an adaptor protein that links phosphorylated receptors and adaptors to SOS-family RAS activators.
GRB2 · growth factor receptor bound protein 2
An adaptor protein that helps recruit SOS-family exchange factors to activated receptor signaling complexes.
Growing fatty acyl-ACP
A fatty-acyl chain carried by acyl carrier protein during fatty-acid synthesis.
Gs–cAMP–PKA Signaling · G alpha(s)-coupled receptor signaling through cyclic AMP and protein kinase A
A common GPCR branch in which Gαs stimulates cyclic AMP production and cAMP regulates protein kinase A and other effectors.
GSK3B · glycogen synthase kinase 3 beta
Encodes a kinase that can restrain glycogen synthase and is regulated by insulin-linked AKT signaling.
GSK3β · glycogen synthase kinase 3 beta
A serine/threonine kinase that can inhibit glycogen synthase through phosphorylation. In insulin signaling, AKT-dependent inhibitory phosphorylation of GSK3B can help favor glycogen synthesis; multiple enzymes and signals regulate glycogen flux.
GSR · glutathione-disulfide reductase
Encodes glutathione reductase, which uses NADPH to regenerate reduced glutathione from glutathione disulfide.
GTP
Guanosine triphosphate formed by substrate-level phosphorylation in the citric acid cycle.
GTPase-activating Proteins · GTPase-activating proteins
Proteins that accelerate GTP hydrolysis by a GTPase, helping return the switch toward its GDP-bound state.
Guanine Nucleotide dissociation inhibitors · Guanine nucleotide dissociation inhibitors
Regulators that bind GDP-bound members of selected small GTPase families and can influence their activity and localization.
Guanine Nucleotide exchange factors · Guanine nucleotide exchange factors
Proteins that help a GTPase release GDP so GTP can bind and activate the switch.
Guanosine monophosphate · GMP
A purine nucleotide formed from IMP and used in RNA and nucleotide metabolism.
GYS1 · NCBI Gene 2997
GYS1 contributes to Glycogen synthase.
GYS2 · NCBI Gene 2998
GYS2 contributes to Glycogen synthase.
Gαs (GNAS) · GNAS complex locus
The stimulatory alpha subunit of a heterotrimeric G protein. In its GTP-bound state, Gαs can stimulate adenylyl cyclase; GNAS has multiple gene products, so this record focuses on the Gαs signaling role.
H. pylori antibodies · Antibodies to Helicobacter pylori
Blood antibodies against H. pylori; they show exposure but cannot distinguish active from past infection.
H. pylori antibody typing panel (antigen targets unspecified) · Helicobacter pylori antibody typing panel
A panel that types blood antibodies against Helicobacter pylori antigens; the antigens it covers were not named.
H. pylori infection · Helicobacter pylori infection
Stomach infection with Helicobacter pylori, a common cause of peptic ulcers that can be cleared with antibiotic treatment.
HADHA · NCBI Gene 3030
HADHA contributes to Mitochondrial trifunctional protein.
Hantavirus Pulmonary syndrome · Hantavirus pulmonary syndrome
A severe respiratory illness associated with infection by New World hantaviruses, including Sin Nombre virus in the United States.
HBB · hemoglobin subunit beta
HBB provides instructions for beta-globin, one of the protein subunits in adult hemoglobin. Particular HBB variants produce hemoglobin S and can cause sickle cell disease when inherited in disease-associated combinations.
HBeAg · Hepatitis B e antigen
A secreted HBV protein associated with active viral replication and high infectivity in a person with HBV infection.
HbS β6 Glu→Val Variant
The HBB missense variant that produces sickle hemoglobin: glutamate is replaced by valine at mature beta-globin residue 6 (often described as p.Glu7Val using precursor numbering).
HBsAg · Hepatitis B surface antigen
A hepatitis B virus surface protein; its presence indicates current HBV infection.
Helicobacter pylori
A Gram-negative bacterium that colonizes the stomach lining and is a major cause of peptic ulcers.
Helper T cell
A CD4⁺ T lymphocyte that coordinates immune responses through cell contacts and secreted signals.
Heme Biosynthesis · human heme biosynthetic pathway
A multi-step route builds heme, the iron-containing cofactor used by hemoglobin and many other proteins.
Hemoglobin S
A hemoglobin tetramer containing sickle beta-globin subunits; deoxygenated molecules can polymerize under susceptible intracellular conditions.
Hepatitis B · Hepatitis B virus infection
Liver infection caused by hepatitis B virus; it can be acute or chronic and is preventable by vaccination.
Hepatitis B virus
A partially double-stranded DNA virus that infects liver cells and causes hepatitis B.
Hepatitis C · Hepatitis C virus infection
Liver infection caused by hepatitis C virus; most infections become chronic, and antiviral treatment cures most people.
Hepatitis C virus · Orthohepacivirus hominis (hepatitis C virus)
A positive-sense RNA virus that infects the liver and causes hepatitis C.
Hepatocyte
Hepatocytes are the main working cells of the liver and carry out many chemical tasks for the body.
HER2 (ERBB2) · erb-b2 receptor tyrosine kinase 2
A member of the ERBB receptor family. HER2 has no established soluble ligand of its own and can participate in signaling as a partner for other ERBB receptors.
HER3 (ERBB3) · erb-b2 receptor tyrosine kinase 3
An ERBB-family receptor with weak intrinsic kinase activity. HER3 can signal by pairing with kinase-active ERBB partners, including HER2.
Hexokinase · EC 2.7.1.1
Transfers a phosphate from ATP to glucose. Hexokinases 1–3 are inhibited by glucose 6-phosphate. Glucokinase is a lower-affinity isozyme found in liver and pancreatic β-cells.
High-throughput Screening · High-throughput screening
Automated testing of many candidate molecules in parallel to find compounds with a desired measurable activity.
Histidine · L-histidine
Histidine is an amino acid with an imidazole ring that can gain or lose a proton near biologically relevant pH.
HIV Antibodies · Antibodies to HIV-1 and HIV-2
Antibodies against HIV-1 or HIV-2, detected by antibody tests and by antigen/antibody combination tests.
HIV Infection · Human immunodeficiency virus infection
Infection with HIV, which targets immune cells; without treatment it can progress to AIDS, and with treatment people can live long, healthy lives.
HK1 · NCBI Gene 3098
HK1 contributes to Hexokinase.
HK2 · NCBI Gene 3099
HK2 contributes to Hexokinase.
HK3 · NCBI Gene 3101
HK3 contributes to Hexokinase.
HMG-CoA reductase · EC 1.1.1.34
NADPH-dependent, rate-limiting enzyme that reduces HMG-CoA to mevalonate.
HMG-CoA Reductase · HMG-CoA reductase
A rate-controlling enzyme in the mevalonate pathway and the molecular target of statin medicines.
HMG-CoA synthase (cytosolic) · EC 2.3.3.10
Condenses acetyl-CoA and acetoacetyl-CoA in the mevalonate pathway.
HMGCL · NCBI Gene 3155
HMGCL contributes to 3-Hydroxy-3-methylglutaryl-CoA lyase.
HMGCR · NCBI Gene 3156
HMGCR contributes to HMG-CoA reductase.
HMGCS1 · NCBI Gene 3157
HMGCS1 contributes to HMG-CoA synthase (cytosolic).
Homeostasis
Regulation that keeps internal conditions within ranges compatible with organism function despite ongoing change.
Homo sapiens · Human
The human species, used here as the organism context for the curated TP53 and p53 records.
Horizontal Gene transfer · Horizontal gene transfer
Movement of genetic material between organisms outside parent-to-offspring inheritance.
How Kinase inhibitors work · How kinase inhibitors work
Kinase inhibitors can bind different structural states or sites and interfere with phosphorylation signaling.
How Statins lower cholesterol · How statins lower cholesterol
Statins inhibit HMG-CoA reductase and can increase hepatic uptake of LDL from the circulation.
Human immunodeficiency virus 1 · HIV-1
A retrovirus that infects immune cells and causes HIV infection; HIV-1 accounts for most infections worldwide.
Human immunodeficiency virus 2 · HIV-2
A retrovirus distinct from HIV-1 that also causes HIV infection; laboratory HIV testing looks for antibodies to both HIV-1 and HIV-2.
Hydrogen Peroxide (H₂O₂) · hydrogen peroxide
Hydrogen peroxide is a reactive oxygen species that can act in signaling but can also contribute to oxidative damage when not controlled.
IDH3A · NCBI Gene 3419
IDH3A contributes to NAD-dependent isocitrate dehydrogenase.
IDH3B · NCBI Gene 3420
IDH3B contributes to NAD-dependent isocitrate dehydrogenase.
IDH3G · NCBI Gene 3421
IDH3G contributes to NAD-dependent isocitrate dehydrogenase.
IDI1 · NCBI Gene 3422
IDI1 contributes to Isopentenyl-diphosphate delta-isomerase.
IGF2R · insulin like growth factor 2 receptor
Encodes the cation-independent mannose-6-phosphate receptor, which also binds IGF2 and helps traffic selected lysosomal enzymes.
Immunoglobulin G
A major class of secreted antibody composed of two heavy and two light chains.
IMP cyclohydrolase · EC 3.5.4.10
Closes the second purine ring to form IMP.
Inclisiran And PCSK9 RNA interference · Inclisiran and PCSK9 RNA interference
A PCSK9-targeting siRNA example that reduces production of the PCSK9 protein in the liver.
Independent Assortment · Independent assortment
The largely independent orientation and segregation of different homologous chromosome pairs during meiosis I.
Infertility Immunological test panel (targets unspecified) · Immunological testing in infertility evaluation
A generic panel of immunological tests associated with infertility evaluation; its targets were not specified.
Innate Immune Response
Rapid, pattern-based defenses that limit infection and help activate adaptive immunity.
Inorganic phosphate · Pi
Free phosphate. GAPDH incorporates it into 1,3-bisphosphoglycerate.
Inosine monophosphate · IMP
The branch-point purine nucleotide precursor to AMP and GMP.
Insulin
A hormone that helps coordinate nutrient use and storage after food intake.
Insulin Receptor · Insulin receptor
A cell-surface receptor that detects insulin and initiates intracellular signaling.
Insulin Signaling · Insulin signaling
How insulin receptor signaling coordinates glucose uptake and nutrient storage.
Intracellular Oxygen transport · globin-mediated oxygen binding in cells
Globin proteins bind oxygen reversibly; hemoglobin carries it in blood, while myoglobin stores and moves oxygen within muscle.
Intron
A transcribed region removed from many eukaryotic RNA precursors during RNA splicing.
Isocitrate
The rearranged six-carbon isomer of citrate.
Isoleucine · L-isoleucine
Isoleucine is one of the three branched-chain amino acids. Its nonpolar side chain often packs inside folded proteins.
Isopentenyl diphosphate · IPP
A five-carbon activated isoprene unit used to build larger isoprenoids.
Isopentenyl-diphosphate delta-isomerase · EC 5.3.3.2
Reversibly interconverts IPP and dimethylallyl diphosphate.
Isovaleryl-CoA
The first committed leucine-derived acyl-CoA intermediate.
Isovaleryl-CoA dehydrogenase · EC 1.3.8.4
Oxidizes isovaleryl-CoA early in leucine catabolism.
IVD · NCBI Gene 3712
IVD contributes to Isovaleryl-CoA dehydrogenase.
JAK–STAT Signaling · JAK–STAT signaling
A direct route from selected cytokine receptors to transcriptional responses.
Keratinocyte
Keratinocytes make up most of the epidermis and help form a protective barrier.
Ketone Bodies · Ketone bodies
Small molecules made mainly by the liver from acetyl-CoA and used as fuel by several tissues during prolonged fasting.
Kidney Metabolism · Kidney metabolism
The kidney supports transport-intensive work and can contribute to glucose production during fasting.
KRAS · KRAS proto-oncogene, GTPase
Encodes a small GTPase that relays signals from receptors to RAF kinases and other effectors when GTP-bound.
KRAS · KRAS proto-oncogene, GTPase
A molecular switch that cycles between GDP-bound and GTP-bound states. Active KRAS can recruit RAF and engage other effectors, including PI3K.
KRAS G12C
A KRAS variant that replaces glycine at position 12 with cysteine and creates a chemically addressable feature in the protein.
L-3-Hydroxyacyl-CoA
The hydrated intermediate in a beta-oxidation turn.
Lanosterol
The first cyclic sterol intermediate in cholesterol synthesis.
Lanosterol synthase · EC 5.4.99.7
Cyclizes 2,3-oxidosqualene to lanosterol.
LDL Clearance and PCSK9 · Human LDL receptor-mediated clearance and PCSK9-dependent receptor degradation
An LDLR trafficking route that helps clear LDL particles from circulation and is regulated by PCSK9.
LDL Particle
A circulating lipoprotein particle that carries cholesterol and is recognized by LDL receptors through apolipoprotein B-100.
LDL Receptor · LDL receptor
A cell-surface receptor that binds LDL particles and helps cells, especially liver cells, remove them from circulation.
Leucine · L-leucine
Leucine is a branched-chain amino acid with a hydrophobic side chain that helps proteins fold and pack.
Leukocyte
Leukocyte is the broad name for a white blood cell, a member of the body's immune and defense systems.
Leydig Cell
Leydig cells produce testosterone in response to hormonal signals.
Ligands And receptors · Ligands and receptors
A ligand is a molecule that binds a specific partner, such as a receptor, and can change its activity.
Light-dependent Reactions · Light-dependent reactions
Thylakoid-membrane reactions that convert absorbed light into ATP and NADPH while oxidizing water and releasing oxygen.
Liver Metabolism · Liver metabolism
The liver coordinates blood glucose, fuel storage and release, lipid metabolism, and nitrogen disposal.
LSS · NCBI Gene 4047
LSS contributes to Lanosterol synthase.
Lymphocyte
A lymphocyte is an immune cell family that includes B cells, T cells, and natural killer cells.
Lysine · L-lysine
Lysine has a long side chain ending in a positively charged amino group, which can interact with negatively charged molecules.
Lysosomal Storage disorders · Lysosomal storage disorders
Inherited conditions in which lysosomal enzyme or transporter defects disrupt breakdown and recycling of cellular material.
Lysosome
An acidic compartment where enzymes digest selected cellular material for recycling and other functions.
Macrophage
Macrophages are tissue immune cells that engulf material and help coordinate defense, cleanup, and repair.
Magnesium ion · Mg2+
A metal cofactor for the kinases and for enolase. Kinases use ATP and ADP as Mg2+ complexes.
Major Human Cell Types · Representative human cell-type atlas
Explore representative cell types across blood, immunity, organs, metabolism, the nervous system, and reproduction. This is a guided starting set, not an exhaustive inventory of every human cell state.
Malate
A four-carbon citric acid cycle intermediate that is oxidized to oxaloacetate.
Malonyl-CoA
The activated two-carbon donor for fatty-acid synthesis; decarboxylation drives chain extension.
Mannose-6-Phosphate
A carbohydrate phosphate tag recognized by mannose-6-phosphate receptors on many soluble lysosomal enzyme cargos.
Mannose-6-phosphate Lysosomal targeting · Mannose-6-phosphate lysosomal targeting
A sorting signal used by many soluble lysosomal enzymes to reach lysosomes through receptor-mediated trafficking.
MAP2K1 · mitogen-activated protein kinase kinase 1
Encodes MEK1, a dual-specificity kinase that phosphorylates and activates ERK1 and ERK2.
MAP2K2 · mitogen-activated protein kinase kinase 2
Encodes MEK2, a dual-specificity kinase that phosphorylates and activates ERK1 and ERK2.
MAPK1 · mitogen-activated protein kinase 1
Encodes ERK2, a kinase activated by MEK proteins that acts on targets in the cytoplasm and nucleus.
MAPK3 · mitogen-activated protein kinase 3
Encodes ERK1, a kinase activated by MEK proteins that acts on targets in the cytoplasm and nucleus.
Maple Syrup urine disease · Branched-chain ketoacid dehydrogenase complex deficiency
A group of inherited disorders that impair breakdown of leucine, isoleucine, and valine.
Mast Cell
Mast cells are tissue-resident immune cells that can rapidly release stored mediators during certain immune reactions.
MCAD Deficiency · Medium-chain acyl-CoA dehydrogenase deficiency
ACADM variants impair the first dehydrogenation step for medium-chain fatty-acid oxidation.
MCCC1 · NCBI Gene 56922
MCCC1 contributes to 3-Methylcrotonyl-CoA carboxylase.
MCCC2 · NCBI Gene 64087
MCCC2 contributes to 3-Methylcrotonyl-CoA carboxylase.
MDH2 · NCBI Gene 4191
MDH2 contributes to Mitochondrial malate dehydrogenase.
MDM2 · MDM2 proto-oncogene
A gene whose protein product is a major negative regulator of p53 stability.
Megakaryocyte
Megakaryocytes are large bone-marrow cells that produce platelets.
Meiosis
Two coordinated divisions that reduce chromosome-set number and generate genetically varied haploid cells in sexual life cycles.
MEK1 (MAP2K1) · mitogen-activated protein kinase kinase 1
A dual-specificity kinase in the MAPK cascade. MEK1 phosphorylates ERK proteins downstream of RAF-family kinases.
MEK2 (MAP2K2) · mitogen-activated protein kinase kinase 2
A dual-specificity kinase in the MAPK cascade. MEK2 phosphorylates ERK proteins downstream of RAF-family kinases.
Melanocyte
Melanocytes make melanin pigment and transfer pigment-containing structures to nearby cells.
Membrane Potential · Membrane potential
A voltage difference across a cell membrane created by unequal ion distributions and selective permeability.
Membrane Transport · Membrane transport
How molecules cross cell membranes through channels, carriers, and pumps.
Memory B Cell
Memory B cells can persist after an immune response and respond more quickly if a related antigen appears again.
Mendelian Inheritance · Mendelian inheritance
Inheritance patterns explained by allele segregation and, for unlinked genes, independent assortment.
Messenger RNA (mRNA)
An RNA molecule that can carry a protein-coding message and can also be regulated by small RNAs or antisense oligonucleotides.
Methionine · L-methionine
Methionine is a sulfur-containing amino acid and is often the first amino acid inserted when a protein is translated.
Methylmalonyl-CoA mutase · EC 5.4.99.2
Rearranges methylmalonyl-CoA to succinyl-CoA after propionyl-CoA metabolism.
Mevalonate
The six-carbon product of HMG-CoA reductase and a committed precursor to isoprenoids.
Mevalonate 5-diphosphate · MVA-5PP
The activated mevalonate intermediate that is decarboxylated to isopentenyl diphosphate.
Mevalonate 5-phosphate · MVA-5P
The first phosphorylated intermediate of the mevalonate pathway.
Mevalonate diphosphate decarboxylase · EC 4.1.1.33
Uses ATP to produce isopentenyl diphosphate from mevalonate diphosphate.
Mevalonate kinase · EC 2.7.1.36
Phosphorylates mevalonate in the cholesterol-biosynthesis pathway.
Microglial Cell
Microglia are resident immune cells that monitor and respond to changes in the central nervous system.
Mitochondrial malate dehydrogenase · EC 1.1.1.37
Oxidizes malate to oxaloacetate while reducing NAD+.
Mitochondrial trifunctional protein · EC 1.1.1.211
Oxidizes L-3-hydroxyacyl-CoA in long-chain fatty-acid beta-oxidation.
Mitosis
Eukaryotic nuclear division that separates replicated chromosomes into two daughter nuclei.
MLST8 · MTOR associated protein, LST8 homolog
Encodes mLST8, a component shared by mTORC1 and mTORC2.
mLST8 (MLST8) · MTOR associated protein, LST8 homolog
A protein subunit found in both mTORC1 and mTORC2.
Molecular Glues · Molecular glues
Small molecules that stabilize or create an interaction between proteins, changing the function or fate of one or both partners.
Molecular oxygen · O2
The terminal electron acceptor in mitochondrial respiration.
Monocyte
Monocytes circulate in blood and can take part in defense and tissue repair.
MTOR · mechanistic target of rapamycin kinase
Encodes the catalytic kinase subunit shared by mTORC1 and mTORC2.
mTOR (MTOR) · mechanistic target of rapamycin kinase
A protein kinase that forms distinct complexes, including mTORC1 and mTORC2. Those complexes have different subunits and functions.
mTORC1 · Mechanistic target of rapamycin complex 1
A nutrient- and growth-responsive protein complex that coordinates cell growth with protein synthesis, nutrient use, and autophagy. It contains MTOR, RPTOR, and other subunits; it is not a single protein.
mTORC2 · Mechanistic target of rapamycin complex 2
A distinct MTOR-containing complex with RICTOR and other subunits. Among its roles, mTORC2 can phosphorylate AKT at serine 473; it differs in composition and regulation from mTORC1.
Muscle Cell
Muscle cells generate force using actin and myosin, but their structure and control differ across tissues.
MUT · NCBI Gene 4594
MUT contributes to Methylmalonyl-CoA mutase.
MVD · NCBI Gene 4597
MVD contributes to Mevalonate diphosphate decarboxylase.
MVK · NCBI Gene 4598
MVK contributes to Mevalonate kinase.
Mycobacterium tuberculosis
The bacterium that causes tuberculosis, spread through the air when a person with TB disease of the lungs or throat coughs or speaks.
NAD-dependent isocitrate dehydrogenase · EC 1.1.1.41
Oxidatively decarboxylates isocitrate to 2-oxoglutarate.
NAD+
Oxidized nicotinamide adenine dinucleotide, an electron acceptor.
NADH
Reduced nicotinamide adenine dinucleotide, which carries electrons away from glycolysis.
NADP+
Oxidized nicotinamide adenine dinucleotide phosphate; it accepts electrons in the oxidative pentose phosphate pathway.
NADPH
Reduced nicotinamide adenine dinucleotide phosphate; it supplies reducing power for biosynthesis and antioxidant defense.
Natural Killer Cell
Natural killer cells are lymphocytes that can respond to some infected or abnormal cells without first learning a unique antigen through a T-cell receptor.
NDUFS1 · NCBI Gene 4719
NDUFS1 contributes to Respiratory complex I.
Neurofibromin (NF1) · neurofibromin 1
A RAS GTPase-activating protein that promotes GTP hydrolysis and can reduce RAS pathway signaling.
Neuron
An excitable cell specialized to receive, integrate, and transmit information through electrical and chemical signaling.
Neutrophil
Neutrophils are fast-responding white blood cells that help control many bacterial and fungal infections.
NF1 · neurofibromin 1
Encodes neurofibromin, a RAS GTPase-activating protein that helps turn off RAS signaling.
Noncoding RNA
RNA molecules that perform functions without serving as templates for protein synthesis.
Nondisjunction
An error in chromosome segregation that can produce cells with an abnormal number of chromosomes.
North American deer mouse
Peromyscus maniculatus, a rodent that serves as an important reservoir host for Sin Nombre virus in the United States.
Nucleolus
A dynamic region inside the nucleus where ribosomal RNA is made and ribosome subunits begin to assemble.
Nucleotide
A building block of DNA or RNA made of a sugar, a phosphate group, and a nitrogen-containing base.
Nucleus
The membrane-bound compartment that contains most eukaryotic DNA.
OGDH · NCBI Gene 4967
OGDH contributes to 2-Oxoglutarate dehydrogenase complex.
Oligodendrocyte
Oligodendrocytes make myelin around parts of axons in the central nervous system.
OMP decarboxylase · EC 4.1.1.23
Decarboxylates OMP to form UMP.
Oocyte
An oocyte is a female germ cell that has entered meiosis and can contribute a haploid genome to an embryo after fertilization.
Open Reading frame (ORF) · Open reading frame (ORF)
A sequence that can be read in one codon frame without an in-frame stop; a long ORF can suggest protein-coding potential but does not prove expression.
Ornithine
A non-protein amino acid regenerated at the end of each urea-cycle turn.
Ornithine transcarbamylase · EC 2.1.3.3
Transfers the carbamoyl group to ornithine to form citrulline.
Orotate
The pyrimidine ring product that receives ribose phosphate to form OMP.
Orotate phosphoribosyltransferase · EC 2.4.2.10
Transfers ribose phosphate from PRPP to orotate to form OMP.
Orotidine 5'-monophosphate · OMP
The ribosylated pyrimidine nucleotide decarboxylated to UMP.
Orthoebolavirus zairense
A species of filovirus that includes viruses responsible for Ebola disease outbreaks.
Orthohantavirus sinnombreense
A hantavirus species whose reservoir in the United States is chiefly the deer mouse and that can cause hantavirus pulmonary syndrome.
Osteoblast
Osteoblasts build new bone matrix and help control its mineralization.
Osteoclast
Osteoclasts break down bone matrix as part of normal bone remodeling.
Osteocyte
Osteocytes are mature bone cells embedded in the matrix they help maintain.
OTC · NCBI Gene 5009
OTC contributes to Ornithine transcarbamylase.
Oxaloacetate · OAA
A four-carbon citric acid cycle intermediate and gluconeogenic precursor.
Oxidation And reduction · Oxidation and reduction
Paired chemical changes in which electrons move from one molecule to another.
Oxidative Phosphorylation · Oxidative phosphorylation in human metabolism
The respiratory chain transfers electrons from NADH and FAD-linked sources to oxygen. Complexes I, III, and IV pump protons; ATP synthase uses the proton-motive force to make ATP from ADP and phosphate.
Oxidative Phosphorylation · Oxidative phosphorylation
Mitochondrial ATP production driven by electron transport and a proton gradient across the inner membrane.
Oxidative Stress · imbalance between oxidant challenge and cellular defenses
Oxidative stress describes a redox disturbance in which oxidant production or exposure exceeds the capacity of protective systems.
Oxidized Glutathione (GSSG) · glutathione disulfide
GSSG is the oxidized form produced when glutathione participates in some peroxide-reduction reactions.
Oxygen Exchange in red blood cells · O2/CO2 exchange in erythrocytes
Hemoglobin takes up oxygen in the lungs and releases it in body tissues while red blood cells help transport carbon dioxide in the opposite direction.
Oxygen Gradient · Oxygen gradient
A spatial difference in oxygen availability that can support different microbial metabolisms in one environment.
p110α (PIK3CA) · phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha
The catalytic subunit of a common class IA PI3K complex. Together with a regulatory subunit, it can phosphorylate PIP2 to form PIP3.
p53 · Cellular tumor antigen p53
A 393-amino-acid transcription factor that helps determine how a stressed cell responds to damage.
p53 Signaling · p53-dependent stress response
A connected response in which stress signals stabilize p53 and influence cell-cycle arrest, repair, or apoptosis.
p85α (PIK3R1) · phosphatidylinositol-3-kinase regulatory subunit 1
A regulatory subunit of class IA PI3K. Receptor-associated signals can recruit the complex and change regulation of its catalytic subunit.
PAH · phenylalanine hydroxylase
Encodes phenylalanine hydroxylase, which converts phenylalanine to tyrosine.
PAICS · NCBI Gene 10606
PAICS contributes to SAICAR synthetase.
Palmitate · C16:0
A 16-carbon saturated fatty acid and the main product of human fatty-acid synthase.
Palmitoyl-CoA · C16-CoA
The activated 16-carbon saturated fatty acid used here to illustrate mitochondrial beta-oxidation.
Pancreatic Alpha Cell
Pancreatic alpha cells release glucagon, a hormone that helps coordinate fuel availability, especially during fasting.
Pancreatic Beta Cell
Pancreatic beta cells release insulin when blood glucose and other signals indicate that fuel is available.
Paneth Cell
Paneth cells release antimicrobial molecules near the base of small-intestinal crypts.
Passive Membrane transport · Passive membrane transport
Movement across a membrane down a concentration or electrochemical gradient without direct energy input from ATP hydrolysis.
Pathogen
A biological agent that can cause disease in a host under particular conditions.
PC · NCBI Gene 5091
PC contributes to Pyruvate carboxylase.
PCK1 · NCBI Gene 5105
PCK1 contributes to Phosphoenolpyruvate carboxykinase (cytosolic).
PCSK9
A protein that can promote LDL-receptor degradation and thereby influence LDL cholesterol levels.
PCSK9–LDLR Complex · Proprotein convertase subtilisin/kexin type 9 bound to LDL receptor
A receptor–ligand complex formed when PCSK9 binds LDLR. This interaction can change receptor trafficking and favor lysosomal degradation rather than recycling.
PDE4D · phosphodiesterase 4D
Encodes a cAMP-selective phosphodiesterase that contributes to localized cyclic AMP turnover.
PDE4D · phosphodiesterase 4D
A cAMP-selective phosphodiesterase isoform that hydrolyzes cyclic AMP to AMP. PDE4D splice variants and localization help shape local signal dynamics.
PDHA1 · NCBI Gene 5160
PDHA1 contributes to Pyruvate dehydrogenase complex.
PDK1 (PDPK1) · 3-phosphoinositide dependent protein kinase 1
A kinase recruited in phosphoinositide signaling that phosphorylates AKT at threonine 308. This is distinct from pyruvate dehydrogenase kinases, which are also abbreviated PDKs.
PDPK1 · 3-phosphoinositide dependent protein kinase 1
Encodes PDK1, a kinase that phosphorylates AKT at a site needed for full activation in the PIP3 signaling network.
Pedigree Analysis · Pedigree analysis
Use of family relationships and trait observations to evaluate possible inheritance patterns.
Pentose Phosphate pathway · Pentose phosphate pathway in human metabolism
The pentose phosphate pathway branches from glucose 6-phosphate. Its oxidative branch makes NADPH and ribulose 5-phosphate; its reversible non-oxidative reactions interconvert pentoses with glycolytic intermediates to match biosynthetic demand.
Pericyte
Pericytes sit alongside endothelial cells on many small blood vessels.
Peroxisome
An organelle that carries out specialized oxidative reactions, including selected steps in lipid metabolism.
PFAS · NCBI Gene 5198
PFAS contributes to FGAM synthetase.
PFKL · NCBI Gene 5211
PFKL contributes to Phosphofructokinase-1.
PFKM · NCBI Gene 5213
PFKM contributes to Phosphofructokinase-1.
PFKP · NCBI Gene 5214
PFKP contributes to Phosphofructokinase-1.
PGAM1 · NCBI Gene 5223
PGAM1 contributes to Phosphoglycerate mutase.
PGAM2 · NCBI Gene 5224
PGAM2 contributes to Phosphoglycerate mutase.
PGD · NCBI Gene 5226
PGD contributes to 6-Phosphogluconate dehydrogenase.
PGK1 · NCBI Gene 5230
PGK1 contributes to Phosphoglycerate kinase.
PGLS · NCBI Gene 25796
PGLS contributes to 6-Phosphogluconolactonase.
PGM1 · NCBI Gene 5236
PGM1 contributes to Phosphoglucomutase 1.
Phage Display · Phage display
A selection method that links a displayed peptide or antibody fragment to the genetic sequence that encodes it.
Phenotype
An observable or measurable characteristic shaped by genetic, developmental, and environmental factors.
Phenylalanine · L-phenylalanine
Phenylalanine has a bulky aromatic side chain that is usually hydrophobic inside a folded protein.
Phenylalanine Metabolism · Phenylalanine metabolism
An amino-acid route that includes conversion of phenylalanine to tyrosine by PAH.
Phenylketonuria (PKU) · PAH-related phenylalanine hydroxylase deficiency
Usually caused by PAH variants that impair conversion of phenylalanine to tyrosine.
Phosphoenolpyruvate · PEP
An enol phosphate with very high phosphoryl-transfer potential.
Phosphoenolpyruvate carboxykinase (cytosolic) · EC 4.1.1.32
Uses GTP to convert oxaloacetate to phosphoenolpyruvate and carbon dioxide.
Phosphofructokinase-1 · EC 2.7.1.11
Catalyzes the committed step of glycolysis. It is inhibited by ATP and citrate and activated by AMP and fructose 2,6-bisphosphate.
Phosphoglucomutase 1 · EC 5.4.2.2
Interconverts glucose 1-phosphate and glucose 6-phosphate.
Phosphoglycerate kinase · EC 2.7.2.3
Transfers the acyl phosphate of 1,3-bisphosphoglycerate to ADP (substrate-level phosphorylation).
Phosphoglycerate mutase · EC 5.4.2.11
Moves the phosphate from carbon 3 to carbon 2. The human enzymes depend on 2,3-bisphosphoglycerate and use a phosphohistidine intermediate.
Phosphomevalonate kinase · EC 2.7.4.2
Adds a second phosphate to mevalonate 5-phosphate.
Photoreceptor Cell
Photoreceptor cells convert light into changes in electrical signaling in the retina.
Photosystem I
A thylakoid protein–pigment complex that re-energizes electrons for reduction of NADP⁺ to NADPH.
Photosystem II
A thylakoid protein–pigment complex that uses light energy to extract electrons from water.
PI3K-AKT-mTOR Signaling · Human PI3K-AKT-mTOR signaling network
A growth- and nutrient-responsive network in which PI3K lipid signals regulate AKT and connect with mTORC1, metabolism, survival, and biosynthesis.
PIK3CA · phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha
Encodes the p110-alpha catalytic subunit of class I PI3K, which can produce PIP3 from PIP2.
PIK3R1 · phosphatidylinositol-3-kinase regulatory subunit 1
Encodes the p85-alpha regulatory subunit found in several class IA PI3K complexes.
PIP3 · Phosphatidylinositol (3,4,5)-trisphosphate
A membrane phospholipid signal made by PI3K from PIP2. PIP3 helps recruit AKT and other proteins to the cell membrane.
PKA Catalytic subunit alpha (PRKACA) · protein kinase cAMP-activated catalytic subunit alpha
A catalytic subunit of protein kinase A. cAMP binding to regulatory subunits of the PKA holoenzyme releases active catalytic subunits; PRKACA is one catalytic isoform.
PKLR · NCBI Gene 5313
PKLR contributes to Pyruvate kinase.
PKM · NCBI Gene 5315
PKM contributes to Pyruvate kinase.
Plasma Cell
Plasma cells are antibody-secreting cells that develop from activated B cells.
Plasma Membrane · Plasma membrane
A selective boundary that separates a cell from its surroundings.
Plasmodium falciparum
A protozoan parasite and a major cause of severe malaria in humans.
PMVK · NCBI Gene 10654
PMVK contributes to Phosphomevalonate kinase.
Podocyte
Podocytes wrap around kidney glomerular capillaries and help form the filtration barrier.
Potassium ion · K+
A monovalent cation that pyruvate kinase requires for activity.
Potency And efficacy · Potency and efficacy
Two different properties: how much drug is needed for an effect and how large an effect the drug can produce.
PPAT · NCBI Gene 5471
PPAT contributes to Glutamine phosphoribosylpyrophosphate amidotransferase.
PRKACA · protein kinase cAMP-activated catalytic subunit alpha
Encodes a catalytic subunit of protein kinase A, a cAMP-regulated protein kinase complex.
Proline · L-proline
Proline has a ring that locks part of the protein backbone into a restricted shape, often introducing a bend.
Promoter
A DNA region near a transcription start site where RNA polymerase and associated proteins assemble to begin transcription.
Propionyl-CoA
A three-carbon acyl-CoA produced during isoleucine and valine breakdown.
Protein Binding pockets · Protein binding pockets
Regions of a protein surface or interior that can accommodate a molecule and support binding.
Protein Druggability · Protein druggability
How well a protein can be reached and modulated by a medicine with useful selectivity and effect.
Protein Folding and Quality Control
How a protein chain adopts and maintains a functional structure, with cellular systems handling misfolded products.
Protein Kinase A (PKA) · cAMP-dependent protein kinase holoenzyme
A cAMP-regulated protein kinase assembled from regulatory and catalytic subunits. cAMP binding to the regulatory subunits can release active catalytic subunits; subunit composition and signaling are context-dependent.
Protein Kinases · Protein kinases
Enzymes that transfer phosphate groups, usually from ATP, onto protein targets.
Protein Phosphatases · Protein phosphatases
Enzymes that remove phosphate groups from proteins and help balance kinase activity.
Protein Phosphorylation · Protein phosphorylation
A reversible chemical modification that can change a protein's activity or interactions.
Proton · H+
Hydrogen ion released with NADH when G3P is oxidized.
Proton-motive Force · Proton-motive force
Stored electrochemical energy created by differences in proton concentration and charge across a membrane.
Proximal Tubule Epithelial Cell
Proximal tubule cells reclaim much of the filtered water and useful solutes from kidney fluid.
PRPS1 · NCBI Gene 5631
PRPS1 contributes to Ribose-phosphate pyrophosphokinase.
PTEN · phosphatase and tensin homolog
Encodes a lipid phosphatase that converts PIP3 back to PIP2 and can restrain PI3K signaling.
PTEN · phosphatase and tensin homolog
A lipid phosphatase that removes a phosphate from PIP3, opposing PI3K and reducing a signal that helps recruit AKT to the membrane.
Punnett Square · Punnett square
A grid for enumerating possible allele combinations from specified parental gametes.
Purine Nucleotide synthesis · Purine nucleotide synthesis in human metabolism
De novo purine synthesis builds the purine ring atom by atom on activated ribose phosphate. The pathway makes IMP, which branches to AMP and GMP. Ring atoms come from glycine, glutamine, aspartate, carbon dioxide, and folate-bound one-carbon units.
PYGL · NCBI Gene 5836
PYGL contributes to Glycogen phosphorylase.
PYGM · NCBI Gene 5837
PYGM contributes to Glycogen phosphorylase.
Pyrimidine Nucleotide synthesis · Pyrimidine nucleotide synthesis in human metabolism
De novo pyrimidine synthesis builds the ring first, then attaches it to activated ribose. CAD performs the first three reactions, dihydroorotate dehydrogenase forms orotate at the inner mitochondrial membrane, and UMPS produces UMP.
Pyrophosphate · PPi
Two linked phosphate groups released during nucleotide activation reactions.
Pyrrolysine · L-pyrrolysine
Pyrrolysine is a rare amino acid used by some microbes, where a special decoding system can insert it into proteins.
Pyruvate
The three-carbon end product of glycolysis. It can be oxidized in mitochondria or reduced to lactate.
Pyruvate carboxylase · EC 6.4.1.1
Biotin-dependent mitochondrial enzyme that carboxylates pyruvate to oxaloacetate.
Pyruvate dehydrogenase complex · EC 1.2.4.1
Mitochondrial multienzyme complex that oxidatively decarboxylates pyruvate to acetyl-CoA.
Pyruvate kinase · EC 2.7.1.40
Transfers the phosphate of PEP to ADP in a strongly exergonic reaction that requires Mg2+ and K+. Fructose 1,6-bisphosphate activates the PKM2 and liver isoforms (feed-forward activation).
Pyruvate Kinase deficiency · PKLR-related red-cell glycolytic disorder
Inherited PKLR variants can reduce red-cell pyruvate kinase activity and impair ATP generation in erythrocytes.
Pyruvate Oxidation · Pyruvate oxidation in human metabolism
The pyruvate dehydrogenase complex links glycolysis to the citric acid cycle by converting pyruvate to acetyl-CoA. It releases carbon dioxide and captures electrons in NADH; its reaction is effectively irreversible in cells.
RAF1 · Raf-1 proto-oncogene, serine/threonine kinase
Encodes a RAF-family kinase that can activate MEK proteins downstream of RAS.
RAF1 (C-RAF) · Raf-1 proto-oncogene, serine/threonine kinase
A RAF-family kinase that can relay RAS signals to MEK. RAF proteins can form dimers, so the pathway is more context-dependent than a single straight chain.
Raptor (RPTOR) · regulatory associated protein of MTOR complex 1
A defining mTORC1 subunit that helps recruit substrates to the complex.
RAS-RAF-MEK-ERK Signaling (MAPK) · Human RAF/MAP kinase cascade
A growth-signal network whose core RAS-RAF-MEK-ERK relay regulates cell responses, with output shaped by feedback, location, and cell context.
Receptor Tyrosine kinase signaling · Receptor tyrosine kinase signaling
How growth-factor receptors use phosphorylation to assemble signaling networks.
Red Blood cell metabolism · Red blood cell metabolism
Mature red blood cells use glucose for ATP and reducing power because they lack mitochondria.
Reduced Glutathione (GSH) · γ-glutamyl-cysteinyl-glycine, reduced form
GSH is a small antioxidant molecule used by enzymes such as GPX1 to reduce peroxides.
Regulatory T Cell
Regulatory T cells help limit immune responses and support immune tolerance.
Resistance To kinase inhibitors · Resistance to kinase inhibitors
Tumor cells can restore signaling or alter drug binding so a kinase inhibitor loses effect.
Respiratory complex I · EC 7.1.1.2
Transfers electrons from NADH to ubiquinone and pumps protons across the inner mitochondrial membrane.
Respiratory complex II · EC 1.3.5.1
Transfers electrons from succinate oxidation to ubiquinone without pumping protons.
Respiratory complex III · EC 7.1.1.8
Transfers electrons from ubiquinol to cytochrome c and contributes to proton translocation.
Retinal Cone Cell
Cone cells support color vision and detailed vision in brighter light.
Retinal Rod Cell
Rod cells are retinal photoreceptors that are highly sensitive to dim light.
RGS Proteins
Regulators of G-protein signaling that accelerate GTP hydrolysis by selected heterotrimeric Gα subunits.
RHEB · Ras homolog, mTORC1 binding
Encodes a small GTPase whose GTP-bound state can activate mTORC1.
RHEB · Ras homolog, mTORC1 binding
A small GTPase that can activate mTORC1 when GTP-bound. The TSC complex regulates the balance between RHEB nucleotide states.
Ribose 5-phosphate · R5P
A pentose used to make PRPP and nucleotide precursors.
Ribose-5-phosphate isomerase · EC 5.3.1.6
Interconverts ribulose 5-phosphate and ribose 5-phosphate.
Ribose-phosphate pyrophosphokinase · EC 2.7.6.1
Activates ribose 5-phosphate to PRPP using ATP.
Ribosome
A ribonucleoprotein molecular machine that reads messenger RNA and assembles amino acids into a polypeptide.
Ribulose 1,5-bisphosphate · RuBP
A five-carbon acceptor regenerated by the Calvin cycle and carboxylated by RuBisCO when carbon dioxide is fixed.
Ribulose 5-phosphate · Ru5P
A five-carbon ketose phosphate that can become ribose 5-phosphate or xylulose 5-phosphate.
Ribulose-phosphate 3-epimerase · EC 5.1.3.1
Interconverts ribulose 5-phosphate and xylulose 5-phosphate.
RICTOR · RPTOR independent companion of MTOR complex 2
Encodes a defining scaffold subunit of mTORC2, which can phosphorylate AKT at serine 473.
RICTOR · RPTOR independent companion of MTOR complex 2
A defining scaffold subunit of mTORC2. The mTORC2 complex can phosphorylate AKT at serine 473.
RNA Interference · RNA interference
A cellular process in which small RNAs guide protein complexes to reduce or regulate matching RNA molecules.
RNA Processing · RNA processing
How many eukaryotic RNA transcripts are modified before they are used.
RNA-induced Silencing complex · RNA-induced silencing complex
A protein complex that uses a guide RNA to recognize and regulate complementary target RNAs.
RNase H1
An enzyme that recognizes RNA–DNA hybrids and can cleave the RNA strand, a mechanism used by some antisense drugs.
RNase H1-Dependent ASO Cleavage
A gapmer antisense oligonucleotide binds a complementary RNA sequence and recruits RNase H1 to cleave the RNA strand of the hybrid.
RPE · NCBI Gene 6120
RPE contributes to Ribulose-phosphate 3-epimerase.
RPIA · NCBI Gene 22934
RPIA contributes to Ribose-5-phosphate isomerase.
RPS6KB1 · ribosomal protein S6 kinase B1
Encodes S6K1, a kinase downstream of mTORC1 that helps regulate protein synthesis and cell growth.
RPTOR · regulatory associated protein of MTOR complex 1
Encodes Raptor, a defining scaffold and substrate-recruitment subunit of mTORC1.
RuBisCO
The enzyme complex that catalyzes CO₂ addition to ribulose 1,5-bisphosphate in the Calvin cycle.
S6K1 (RPS6KB1) · ribosomal protein S6 kinase B1
A kinase that can be activated downstream of mTORC1 and phosphorylate targets involved in protein synthesis and cell growth.
SAICAR synthetase · EC 6.3.4.13
Adds aspartate to CAIR; the product is then cleaved to AICAR and fumarate.
Schwann Cell
Schwann cells support peripheral nerves and can wrap axons with myelin.
SDHA · NCBI Gene 6389
SDHA contributes to Respiratory complex II.
Second Messengers · Second messengers
Small intracellular signals that relay and distribute information after many receptors are activated.
Sedoheptulose 7-phosphate · S7P
A seven-carbon sugar phosphate formed by transketolase.
Selenocysteine · L-selenocysteine
Selenocysteine is a rare amino acid that cells can insert into certain proteins using a special recoding system.
Serine · L-serine
Serine is a polar amino acid with a hydroxyl group that can form hydrogen bonds and be chemically modified.
Sertoli Cell
Sertoli cells support developing sperm cells inside the seminiferous tubules.
SHC1 · SHC adaptor protein 1
Encodes an adaptor protein that helps connect activated receptors with downstream signaling proteins.
SHC1 · SHC adaptor protein 1
An adaptor protein that can help assemble signaling complexes downstream of activated cell-surface receptors.
Shortened fatty acyl-CoA
A generic fatty acyl-CoA chain that is two carbons shorter after one beta-oxidation turn.
Sickle Cell disease · inherited hemoglobin disorders involving hemoglobin S
A group of inherited blood disorders in which hemoglobin S is present with another disease-associated HBB allele. Low-oxygen HbS can form fibers, making red blood cells rigid and contributing to anemia and blocked blood flow.
Signal Amplification · Signal amplification
A signaling process in which one activated component influences many downstream molecules.
siRNA Therapeutics · siRNA therapeutics
Short double-stranded RNAs that guide cellular RNA-interference machinery to a complementary target RNA.
Skeletal Muscle Cell
Skeletal muscle cells generate force for movement and posture and can respond to voluntary motor commands.
Skeletal Muscle metabolism · Skeletal muscle metabolism
Muscle uses circulating and stored fuels to meet the changing energy demand of contraction.
SLC37A4 · solute carrier family 37 member 4
Encodes the glucose-6-phosphate transporter associated with GSD type Ib.
SMN1 · survival of motor neuron 1, telomeric
Encodes the SMN protein needed by motor neurons; loss of both functional copies causes most spinal muscular atrophy.
Smooth Muscle Cell
Smooth muscle cells change the diameter of vessels and move or regulate material through hollow organs.
SOD1-targeted Antisense research · SOD1-targeted antisense research
An example of using an antisense drug to reduce RNA from a disease-associated gene rather than inhibit its protein product.
SOS1 · SOS Ras/Rac guanine nucleotide exchange factor 1
Encodes a guanine-nucleotide exchange factor that promotes GDP-to-GTP exchange on RAS proteins.
SOS1 · SOS Ras/Rac guanine nucleotide exchange factor 1
A RAS guanine-nucleotide exchange factor. When recruited to signaling complexes, SOS1 can promote the active, GTP-bound state of RAS.
Sperm Cell
A sperm cell is a mature male gamete that can deliver a haploid genome to an egg during fertilization.
Spinal Muscular atrophy · SMN1-related (5q) spinal muscular atrophy
An inherited condition in which loss of motor neurons causes progressive muscle weakness; most cases are due to loss of both working SMN1 copies.
Squalene
A 30-carbon linear triterpene formed from two farnesyl diphosphate molecules.
Squalene synthase · EC 2.5.1.21
Combines two farnesyl diphosphate molecules to form squalene.
Steric-Blocking ASO Mechanisms
An antisense oligonucleotide binds RNA and blocks access by selected molecular partners, potentially changing splicing, translation, or RNA stability without RNase H1 cleavage.
Sterol-processing enzymes · EC 1.14.14.154
A simplified group label for demethylation, reduction, and double-bond rearrangements that convert lanosterol to cholesterol.
Substrate Reduction therapy · Substrate reduction therapy
A strategy that lowers production of a material that accumulates when its breakdown pathway is impaired.
Substrate-level Phosphorylation · Substrate-level phosphorylation
Direct formation of ATP or GTP when an enzyme transfers a phosphate group from a reaction intermediate.
Succinate
A four-carbon citric acid cycle intermediate.
Succinate dehydrogenase · EC 1.3.5.1
TCA-cycle enzyme and respiratory complex II that oxidizes succinate to fumarate.
Succinyl-CoA
A four-carbon, high-energy thioester intermediate of the citric acid cycle.
Succinyl-CoA synthetase · EC 6.2.1.4
Couples succinyl-CoA cleavage to GTP formation in the mitochondrial matrix.
Succinylaminoimidazole carboxamide ribonucleotide · SAICAR
The aspartate-containing intermediate cleaved to AICAR and fumarate.
SUCLG1 · NCBI Gene 8802
SUCLG1 contributes to Succinyl-CoA synthetase.
SUCLG2 · NCBI Gene 8801
SUCLG2 contributes to Succinyl-CoA synthetase.
Synaptic Transmission · Synaptic transmission
Communication from a neuron to another cell at a specialized junction, often using neurotransmitter release and receptors.
Syphilis · Infection with Treponema pallidum subspecies pallidum
A sexually transmitted bacterial infection that progresses through stages if untreated and can pass to a fetus during pregnancy; it is curable with antibiotics.
Systemic Lupus erythematosus · Systemic lupus erythematosus (lupus)
A chronic autoimmune disease in which the immune system attacks the body's own tissues, affecting skin, joints, kidneys, blood cells, and other organs.
T Cell
T cells are lymphocytes whose receptors recognize specific molecular fragments displayed by other cells.
TALDO1 · NCBI Gene 6888
TALDO1 contributes to Transaldolase.
Target Engagement · Target engagement
Evidence that a candidate medicine binds or otherwise interacts with its intended biological target in a relevant setting.
TB Antibody test (unspecified) · Unspecified antibody-based test for Mycobacterium tuberculosis
An unspecified antibody-based tuberculosis test; antibody tests are not recommended for diagnosing active TB.
TBC1D4 · TBC1 domain family member 4
Encodes a Rab GTPase-activating protein that helps regulate insulin-responsive GLUT4 vesicle traffic.
TBC1D4 (AS160) · TBC1 domain family member 4
A Rab GTPase-activating protein that regulates GLUT4 vesicle traffic. Insulin-linked AKT phosphorylation of TBC1D4 is an important part of GLUT4 regulation in muscle and adipose cells; other signals and trafficking steps also contribute.
Tetrahydrofolate · THF
The folate cofactor left after a one-carbon transfer.
TGF-β Signaling · TGF-β signaling
A receptor-kinase network that regulates development, immune responses, and tissue remodeling.
The Cell · The cell
The smallest unit that can carry out the processes of life.
The Genetic code · The genetic code
Rules that relate three-base RNA codons to amino acids or translation stop signals.
The Small GTPase switch · The small GTPase switch
A molecular switch in which a small GTPase's bound GDP or GTP helps control its interactions with signaling partners.
Therapeutic Antibodies · Therapeutic antibodies
Medicines made from antibodies that recognize targets such as receptors, soluble proteins, or cell-surface markers.
Threonine · L-threonine
Threonine is an essential amino acid with a hydroxyl group that can form hydrogen bonds.
Thylakoid
An internal chloroplast membrane sac that carries photosystems, electron-transfer complexes, and ATP synthase.
TKT · NCBI Gene 7086
TKT contributes to Transketolase.
TP53 · tumor protein p53
A protein-coding gene whose product helps cells respond to stress by regulating cell-cycle arrest, DNA repair, senescence, and apoptosis.
TPI1 · NCBI Gene 7167
TPI1 contributes to Triose-phosphate isomerase.
trans-2-Enoyl-ACP
The dehydrated intermediate in fatty-acid synthase elongation.
trans-2-Enoyl-CoA
The enoyl-CoA intermediate made in the first oxidation of a beta-oxidation turn.
Transaldolase · EC 2.2.1.2
Transfers a three-carbon unit between sugar phosphates in the non-oxidative branch.
Transcription
The process of making an RNA copy from a DNA template.
Transcription Start site · Transcription start site
The DNA position where RNA polymerase begins synthesizing a particular RNA transcript.
Transketolase · EC 2.2.1.1
Transfers two-carbon units between sugar phosphates in the non-oxidative pentose phosphate pathway.
Translation
How ribosomes read mRNA and build a protein from amino acids.
Transport Vesicle · Transport vesicle
A small membrane-bound carrier that moves selected cargo between cellular compartments or to the cell surface.
Treponema pallidum
The spirochete bacterium species that includes the subspecies causing syphilis.
Treponema pallidum antibodies · Treponemal antibodies to Treponema pallidum
Antibodies specific to the syphilis bacterium, detected by treponemal tests; they usually persist for life.
Triose-phosphate isomerase · EC 5.3.1.1
Interconverts dihydroxyacetone phosphate and glyceraldehyde 3-phosphate.
Tryptophan · L-tryptophan
Tryptophan has a large indole ring that can contribute to protein packing and absorb ultraviolet light.
TSC1 · TSC complex subunit 1
Encodes hamartin, a component of the TSC1–TSC2 complex that restrains RHEB–mTORC1 signaling.
TSC1 (hamartin) · TSC complex subunit 1
A component of the TSC1–TSC2 protein complex, which acts upstream of RHEB and helps regulate mTORC1.
TSC1–TSC2 Complex · Tuberous sclerosis protein complex
TSC1 and TSC2 form a regulatory complex that acts as a GTPase-activating protein for RHEB. This helps restrain RHEB-driven mTORC1 activity.
TSC2 · TSC complex subunit 2
Encodes tuberin, a RHEB GTPase-activating component of the TSC1–TSC2 complex.
TSC2 (tuberin) · TSC complex subunit 2
A catalytic component of the TSC1–TSC2 complex that promotes conversion of active RHEB-GTP toward RHEB-GDP, reducing mTORC1 activation.
Tuberculosis · Infection or disease caused by Mycobacterium tuberculosis
An airborne bacterial disease that usually affects the lungs; infection can stay inactive or progress to TB disease, which is treatable and curable.
Type I Alveolar Cell
Type I alveolar cells form much of the thin surface across which oxygen and carbon dioxide exchange.
Type II Alveolar Cell
Type II alveolar cells make pulmonary surfactant, which helps keep alveoli from collapsing during breathing.
Tyrosine · L-tyrosine
Tyrosine is an aromatic amino acid with a hydroxyl group that makes it more polar than phenylalanine.
Ubiquinol · CoQH2
The reduced form of ubiquinone that transfers electrons to complex III.
Ubiquinone · CoQ
A membrane-soluble electron carrier in the respiratory chain.
UDP
Uridine diphosphate released when UDP-glucose donates a glucose residue.
UDP-glucose · UDP-Glc
An activated glucose donor used by glycogen synthase.
UDP-glucose pyrophosphorylase · EC 2.7.7.9
Activates glucose 1-phosphate with UTP to form UDP-glucose.
UGP2 · NCBI Gene 7360
UGP2 contributes to UDP-glucose pyrophosphorylase.
UMPS · NCBI Gene 7372
UMPS contributes to OMP decarboxylase.
UQCRC1 · NCBI Gene 7384
UQCRC1 contributes to Respiratory complex III.
Urea
The small nitrogen-containing molecule used by humans to excrete excess nitrogen.
Urea Cycle · Urea cycle in human metabolism
The liver urea cycle packages two nitrogen atoms into urea for excretion. One nitrogen enters as mitochondrial ammonia and the other as cytosolic aspartate; ornithine is regenerated after each turn.
Uridine monophosphate · UMP
The first pyrimidine nucleotide produced de novo; it can be phosphorylated to UTP and CTP.
Uridine triphosphate · UTP
A pyrimidine triphosphate used in RNA synthesis and as an activated sugar donor.
Vaccination
An intervention that presents antigenic information to the immune system to help establish protective responses and memory.
Valine · L-valine
Valine is a branched-chain amino acid with a hydrophobic side chain that helps shape protein interiors.
Very-long-chain acyl-CoA dehydrogenase · EC 1.3.8.9
Catalyzes the first oxidation in long-chain mitochondrial beta-oxidation.
Vesicle Transport · Vesicle transport
Membrane-bound carriers that move selected cargo between compartments or to and from the cell surface.
Viral Hepatitis serology panel (components unspecified) · Viral hepatitis serology panel
A broad blood-test panel for viral hepatitis; the specific markers it includes were not named.
Virus
An acellular infectious agent whose replication depends on host-cell machinery.
Voltage-Gated Ion Channel
A family of membrane-spanning protein channels whose opening or closing is influenced by membrane voltage and whose ion selectivity depends on channel structure.
Water · H2O
Removed from 2-phosphoglycerate by enolase.
Wnt Signaling · Wnt signaling
A family of signals with important roles in development, tissue renewal, and cell fate.
Xylulose 5-phosphate · X5P
A ketopentose that donates two-carbon units in non-oxidative pentose phosphate reactions.
β-arrestin
Adaptor proteins that can reduce GPCR coupling to G proteins and organize receptor trafficking or other signaling events.