Isocitrate dehydrogenase [NAD] subunit gamma, mitochondrial (IDH3G)

Isocitrate dehydrogenase [NAD] subunit gamma, mitochondrial (IDH3G), is the gamma subunit of the heterotetrameric, NAD+-dependent isocitrate dehydrogenase 3 (IDH3) complex in mitochondria, which catalyzes the irreversible oxidative decarboxylation of isocitrate to α-ketoglutarate in the tricarboxylic acid (TCA) cycle, generating NADH for ATP synthesis[1][3][5]. IDH3G encodes a non-catalytic, regulatory subunit that, together with the alpha and beta subunits, is essential for the proper allosteric regulation and maximal enzymatic activity of the IDH3 holoenzyme[5][2]. IDH3G is primarily involved in energy metabolism and is different from the well-studied cancer targets IDH1 and IDH2, as no recurrent cancer-associated gain-of-function or neomorphic mutations, nor targeted drugs, have been reported for IDH3G. However, the gene may play a role in diseases of energy metabolism, cancer drug resistance (e.g., gastric cancer), and rare developmental disorders[5][3]. IDH3G is thus classified as an **enzyme** subunit rather than a catalytic target itself, and while it is essential for mitochondrial energy homeostasis, it is not currently a direct target of any approved therapeutics.

Other names

Isocitrate dehydrogenase (NAD(+)) 3 non-catalytic subunit gammaIDH3GIsocitrate dehydrogenase 3 gammaIsocitrate dehydrogenase 3 (NAD+) gammaIsocitrate dehydrogenase [NAD] subunit gamma, mitochondrialIsocitric dehydrogenase subunit gammaNAD(+)-specific ICDH subunit gammaNAD(H)-specific isocitrate dehydrogenase gamma subunitIsocitrate dehydrogenase, NAD(+)-specific, mitochondrial, gamma subunitH-IDHGRP99

Not established for any specific drugs; as a regulatory/noncatalytic subunit, not a direct drug target like IDH1/2 in oncology