Reaction: isocitrate + NAD+ => alpha-ketoglutarate + CO2 + NADH + H+ [IDH3]
- in pathway: Citric acid cycle (TCA cycle)
Mitochondrial isocitrate dehydrogenase IDH3 catalyzes the irreversible reaction of isocitrate and NAD+ to form alpha ketoglutarate, CO2, and NADH + H+. The enzyme is a heteromer containing four polypeptide chains, two IDH3A, one IDH3B, and one IDH3G, and two Mn++ (Dange and Colman 2010). It is activated by ADP (Soundar et al. 2003, 2006; Bzymek and Colman 2007). This is the first of four oxidation reactions in the citric acid cycle, and the first decarboxylation.
Reaction - small molecule participants:
2OG [mitochondrial matrix]
H+ [mitochondrial matrix]
NADH [mitochondrial matrix]
CO2 [mitochondrial matrix]
NAD+ [mitochondrial matrix]
ISCIT [mitochondrial matrix]
Reactome.org reaction link: R-HSA-70967
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Reaction input - small molecules:
NAD(1-)
D-threo-isocitrate(3-)
Reaction output - small molecules:
2-oxoglutarate(2-)
hydron
NADH(2-)
carbon dioxide
Reactome.org link: R-HSA-70967