Triose phosphate isomerase
What it does, reaction by reaction
Fructose Metabolism (Fructolysis) Carbohydrate Metabolism · Cytosol
Dihydroxyacetone phosphate ↔ glyceraldehyde-3-phosphate
Converts Dihydroxyacetone phosphate into Glyceraldehyde-3-phosphate
› Notes
Triose phosphate isomerase reversibly interconverts the products of fructolysis as needed for downstream glycolysis or gluconeogenesis. No additional ATP or redox cofactor is used.
Gluconeogenesis Carbohydrate Metabolism · Cytosol + mitochondrion + ER
Glyceraldehyde-3-phosphate ↔ dihydroxyacetone phosphate
Converts Glyceraldehyde-3-phosphate into Dihydroxyacetone phosphate
› Notes
Triose phosphate isomerase reversibly interconverts the trioses. One glyceraldehyde-3-phosphate remains unchanged, while the other is isomerized for condensation.
Glycolysis Carbohydrate Metabolism · Cytosol
Dihydroxyacetone phosphate → glyceraldehyde-3-phosphate
Converts Dihydroxyacetone phosphate into Glyceraldehyde-3-phosphate
› Notes
Triose phosphate isomerase reversibly interconverts the two trioses through an enediol intermediate. Only glyceraldehyde-3-phosphate continues directly through the payoff reactions, so one glucose yields two glyceraldehyde-3-phosphate molecules from this point onward.
Anaerobic Glycolysis / Lactic Acid Fermentation Energy Metabolism & Cellular Respiration · Cytosol
Dihydroxyacetone phosphate ⇌ glyceraldehyde-3-phosphate
Converts Dihydroxyacetone phosphate into Glyceraldehyde-3-phosphate
› Notes
Required cofactor: none. This reversible step ensures that both three-carbon products proceed as glyceraldehyde-3-phosphate; from this point, steps 6–10 occur twice per glucose.
Showing all 4 reactions.
What accelerates and inhibits it
Regulation is pathway-specific, so each context is listed separately
No regulation recorded for this enzyme in the source documents.
Recent literature
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