isocitrate + NAD+ => alpha-ketoglutarate + CO2 + NADH + H+ [IDH3] EC Number: 1.1.1.41 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. Pubmed14555658 Pubmed16737955 Pubmed17432878 Pubmed20435888 Reactome Database ID Release 4370967 Reactome, http://www.reactome.org ReactomeREACT_1068