Isocitrate Dehydrogenase 3 (NAD+) Gamma (IDH3G) Human Recombinant Protein

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. NAD(+)-dependent isocitrate dehydrogenases catalyze the allosterically regulated rate-limiting step of the tricarboxylic acid cycle. Each isozyme is a heterotetramer that is composed of two alpha subunits, one beta subunit, and one gamma subunit. The protein encoded by this gene is the gamma subunit of one isozyme of NAD(+)-dependent isocitrate dehydrogenase. This gene is a candidate gene for periventricular heterotopia. Several alternatively spliced transcript variants of this gene have been described, but only some of their full length natures have been determined. [provided by RefSeq, Jul 2008]

IDH3G: a enzyme that that catalyzes the oxidative decarboxylation of isocitrate to alpha-ketoglutarate (alpha-KG), requiring nicotinamide adenine dinucleotide (NAD) as a cofactor. The holoenzyme is a heterooligomer of subunits alpha, beta, and gamma in the apparent ratio of 2:1:1. IDH3 is a mitochondrial enzyme that functions in the Krebs cycle, which generates substrates for cellular respiration. Alpha-KG can exit the mitochondria and enter other cellular compartments where it is a cofactor for the dioxygenases that hydroxylate the transcription factor HIF and trigger its degradation by VHL. Since HIF turns on oncogenic pathways, IDH3 may have tumor suppressor activity. Two isoforms of the human protein are produced by alternative splicing.

Protein type: Carbohydrate Metabolism - citrate (TCA) cycle; Oxidoreductase; EC 1.1.1.41; Mitochondrial

Chromosomal Location of Human Ortholog: Xq28

Cellular Component: nucleoplasm; mitochondrion; mitochondrial matrix; nucleolus

Molecular Function: magnesium ion binding; isocitrate dehydrogenase (NAD+) activity; NAD binding; ATP binding

Biological Process: isocitrate metabolic process; cellular metabolic process; tricarboxylic acid cycle; carbohydrate metabolic process