Background：Isocitrate dehydrogenases catalyze the oxidative decarboxylation of isocitrate to 2-oxoglutarate. These enzymes belong to two distinct subclasses, one of which utilizes NAD（+） as the electron acceptor and the other NADP（+）. Five isocitrate dehydrogenases have been reported： three NAD（+）-dependent isocitrate dehydrogenases, which localize to the mitochondrial matrix, and two NADP（+）-dependent isocitrate dehydrogenases, one of which is mitochondrial and the other predominantly cytosolic. Each NADP（+）-dependent isozyme is a homodimer. The protein encoded by this gene is the NADP（+）-dependent isocitrate dehydrogenase found in the mitochondria. It plays a role in intermediary metabolism and energy production. This protein may tightly associate or interact with the pyruvate dehydrogenase complex. Alternative splicing results in multiple transcript variants.
