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146 recordsATP
Adenosine triphosphate, the cell's main short-term energy carrier.
Glucose · Glc
A six-carbon sugar and the starting fuel for glycolysis.
DNA
A double-stranded molecule whose sequence stores and passes on hereditary information in most cells.
Pyruvate
The three-carbon end product of glycolysis. It can be oxidized in mitochondria or reduced to lactate.
NADH
Reduced nicotinamide adenine dinucleotide, which carries electrons away from glycolysis.
Water · H2O
Removed from 2-phosphoglycerate by enolase.
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-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-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-Phosphoglycerate · 3PG
The product of the first ATP-generating step.
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.
6-Phosphogluconate · 6PG
The hydrolyzed lactone intermediate oxidized to ribulose 5-phosphate.
6-Phosphoglucono-1,5-lactone · 6PGL
The first oxidized intermediate of the pentose phosphate pathway.
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.
Adenosine monophosphate · AMP
A purine nucleotide formed from IMP and used in RNA, energy transfer, and signaling.
ADP
Adenosine diphosphate, formed when ATP gives up a phosphate and recharged to ATP in the payoff phase.
Alanine · L-alanine
Alanine is a compact amino acid used to build proteins. Its small, nonpolar side chain can fit into many protein structures.
Ammonium · NH4+
The protonated form of ammonia; a nitrogen source used by carbamoyl-phosphate synthetase I.
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.
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.
Bicarbonate · HCO3−
Dissolved inorganic carbon used in carboxylation reactions.
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 amino acids
Leucine, isoleucine, and valine, shown together at their shared first catabolic steps.
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.
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.
Carboxyaminoimidazole ribonucleotide · CAIR
A carboxylated intermediate in purine-ring assembly.
Chlorophyll
A family of light-absorbing pigments that transfers excitation energy to photosynthetic reaction centers.
Cholesterol
A membrane sterol and precursor for steroid hormones, bile acids, and vitamin D.
Citrate
A six-carbon citric acid cycle intermediate formed from acetyl-CoA and oxaloacetate.
Citrulline
A urea-cycle intermediate exported from the mitochondrial matrix to the cytosol.
Coenzyme A · CoA
A carrier of activated acyl groups.
Cyclic AMP
A small intracellular second messenger made by adenylyl cyclases downstream of selected receptors.
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.
Dihydroorotate · DHO
A cyclic intermediate oxidized to orotate in 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.
Erythrose 4-phosphate · E4P
A four-carbon sugar phosphate used in biosynthetic pathways.
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.
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.
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.
Fumarate
A four-carbon citric acid cycle intermediate and product of argininosuccinate cleavage.
GDP
Guanosine diphosphate; it accepts a phosphate in the succinyl-CoA synthetase reaction.
Geranyl diphosphate · GPP
A ten-carbon prenyl intermediate formed from DMAPP and IPP.
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.
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.
Glyceraldehyde 3-phosphate · G3P
The three-carbon aldose phosphate that enters the payoff phase. Each glucose yields two.
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.
Growing fatty acyl-ACP
A fatty-acyl chain carried by acyl carrier protein during fatty-acid synthesis.
GTP
Guanosine triphosphate formed by substrate-level phosphorylation in the citric acid cycle.
Guanosine monophosphate · GMP
A purine nucleotide formed from IMP and used in RNA and nucleotide metabolism.
Histidine · L-histidine
Histidine is an amino acid with an imidazole ring that can gain or lose a proton near biologically relevant pH.
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.
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.
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.
Isovaleryl-CoA
The first committed leucine-derived acyl-CoA intermediate.
L-3-Hydroxyacyl-CoA
The hydrated intermediate in a beta-oxidation turn.
Lanosterol
The first cyclic sterol intermediate in cholesterol synthesis.
Leucine · L-leucine
Leucine is a branched-chain amino acid with a hydrophobic side chain that helps proteins fold and pack.
Lysine · L-lysine
Lysine has a long side chain ending in a positively charged amino group, which can interact with negatively charged molecules.
Magnesium ion · Mg2+
A metal cofactor for the kinases and for enolase. Kinases use ATP and ADP as Mg2+ complexes.
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.
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.
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.
Molecular oxygen · O2
The terminal electron acceptor in mitochondrial respiration.
NAD+
Oxidized nicotinamide adenine dinucleotide, an electron acceptor.
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.
Ornithine
A non-protein amino acid regenerated at the end of each urea-cycle turn.
Orotate
The pyrimidine ring product that receives ribose phosphate to form OMP.
Orotidine 5'-monophosphate · OMP
The ribosylated pyrimidine nucleotide decarboxylated to UMP.
Oxaloacetate · OAA
A four-carbon citric acid cycle intermediate and gluconeogenic precursor.
Oxidized Glutathione (GSSG) · glutathione disulfide
GSSG is the oxidized form produced when glutathione participates in some peroxide-reduction reactions.
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.
Phenylalanine · L-phenylalanine
Phenylalanine has a bulky aromatic side chain that is usually hydrophobic inside a folded protein.
Phosphoenolpyruvate · PEP
An enol phosphate with very high phosphoryl-transfer potential.
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.
Potassium ion · K+
A monovalent cation that pyruvate kinase requires for activity.
Proline · L-proline
Proline has a ring that locks part of the protein backbone into a restricted shape, often introducing a bend.
Propionyl-CoA
A three-carbon acyl-CoA produced during isoleucine and valine breakdown.
Proton · H+
Hydrogen ion released with NADH when G3P is oxidized.
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.
Reduced Glutathione (GSH) · γ-glutamyl-cysteinyl-glycine, reduced form
GSH is a small antioxidant molecule used by enzymes such as GPX1 to reduce peroxides.
Ribose 5-phosphate · R5P
A pentose used to make PRPP and nucleotide precursors.
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.
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.
Shortened fatty acyl-CoA
A generic fatty acyl-CoA chain that is two carbons shorter after one beta-oxidation turn.
Squalene
A 30-carbon linear triterpene formed from two farnesyl diphosphate molecules.
Succinate
A four-carbon citric acid cycle intermediate.
Succinyl-CoA
A four-carbon, high-energy thioester intermediate of the citric acid cycle.
Succinylaminoimidazole carboxamide ribonucleotide · SAICAR
The aspartate-containing intermediate cleaved to AICAR and fumarate.
Tetrahydrofolate · THF
The folate cofactor left after a one-carbon transfer.
Threonine · L-threonine
Threonine is an essential amino acid with a hydroxyl group that can form hydrogen bonds.
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.
Tryptophan · L-tryptophan
Tryptophan has a large indole ring that can contribute to protein packing and absorb ultraviolet light.
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.
Urea
The small nitrogen-containing molecule used by humans to excrete excess nitrogen.
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.
Valine · L-valine
Valine is a branched-chain amino acid with a hydrophobic side chain that helps shape protein interiors.
Xylulose 5-phosphate · X5P
A ketopentose that donates two-carbon units in non-oxidative pentose phosphate reactions.