Isocitrate dehydrogenase [NAD] subunit gamma(IDH3G) mitochondrial is a member of the isocitrate and isopropylmalate dehydrogenases family. Isocitrate dehydrogenases catalyze the oxidative decarboxylation of isocitrate to 2-oxoglutarate. The IDH3G is a gamma subunit of one isozyme of isocitrate dehydrogenase which belongs to a distinct subclass, which utilizes NAD(+) as the electron acceptor, and is restricted to the mitochondrial matrix.