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Pathway

Pyruvate oxidation

Homo sapiens · Mitochondrial matrix · 1 reactions

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.

REACTOME IDENTIFIERR-HSA-70268View source record ↗

Net yield per pyruvate

COMPUTED FROM REACTION STOICHIOMETRY
1Acetyl-CoA1 made
1NADH1 made
1Carbon dioxide1 made
OVERALL REACTION

Pyruvate + CoA + NAD+ → Acetyl-CoA + Carbon dioxide + NADH + H+

Overview

EXPLORE BY LEVEL

Pyruvate oxidation is a set of connected chemical steps in human cells. The pyruvate dehydrogenase complex links glycolysis to the citric acid cycle by converting pyruvate to acetyl-CoA. It releases and captures electrons in ; its reaction is effectively irreversible in cells.

WHY THE FLOW CHANGES

Regulation

Compare fed and fasting

The pyruvate dehydrogenase complex responds to fuel and energy status.

Can slow downATP, NADH, and acetyl-CoA

These products and high-energy signals favor inhibitory phosphorylation of the complex.

Can speed upPyruvate, ADP, and calcium in working muscle

These signals favor active pyruvate dehydrogenase and help match oxidation to demand.

Context mattersInsulin

Insulin can promote pyruvate oxidation in selected tissues; effects depend on tissue and nutritional state.

How to read this map

This is an instructional map of selected reactions, not a complete inventory of every reaction in the body. Some steps are grouped; transport, alternate routes, tissue differences, or full molecule balances may be summarized. The Research notes explain this map’s specific limits.

Explore the reaction map and enzyme steps

Pathway map

GENERATED FROM STRUCTURED REACTIONS

Select a molecule or enzyme to inspect it. Select a step number to open its full reaction detail.

  1. Oxidative decarboxylation

    A three-carbon pyruvate loses one carbon as CO2 and transfers the remaining acetyl group to coenzyme A.

    1. Step 1Irreversible · CoA + NAD+ → CO2 + NADH + H+

Reaction steps

1Pyruvate dehydrogenase reactionPyruvate → Acetyl-CoAIrreversible

The multienzyme complex oxidizes pyruvate, releases CO2, and forms acetyl-CoA and NADH.

REACTION · PER TURN + + yields + + +
Enzyme
EC 1.2.4.1 ↗
Cofactors
NAD+ is consumed as a co-substrate (see reaction).
Reversibility
Irreversible under cellular conditions. This is a control point.
Runs per pyruvate
Once
Stage
Oxidative decarboxylation
MECHANISM & CONTEXT

The reaction uses thiamine pyrophosphate, lipoamide, FAD, CoA, and NAD+. Regulation by phosphorylation and product feedback adjusts entry of carbohydrate carbon into mitochondrial oxidation.

Evidence for this step: Pyruvate metabolism (R-HSA-70268)

Research sources, claims, and curation

Pyruvate metabolism (R-HSA-70268)

Reactome · Homo sapiens · Reviewed Reactome human pathway used for reaction sequence and context.

Claims

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.

Curation notes

  • The equation uses the common biochemical convention that NADH formation is accompanied by H+.
  • Pyruvate dehydrogenase is a one-way link under cellular conditions; mammals do not convert acetyl-CoA back to pyruvate.