IDH3A

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 alpha subunit of one isozyme of NAD(+)-dependent isocitrate dehydrogenase. [provided by RefSeq, Jul 2008]

异柠檬酸脱氢酶催化异柠檬酸氧化脱羧生成2-氧代谷氨酸。这些酶分为两个不同的亚类，其一以NAD(+)作为电子受体，另一以NADP(+)为电子受体。目前已报道五种异柠檬酸脱氢酶：三种依赖于NAD(+)的异柠檬酸脱氢酶定位于线粒体基质，两种依赖于NADP(+)的异柠檬酸脱氢酶，其中一种位于线粒体，另一种主要存在于细胞质中。依赖于NAD(+)的异柠檬酸脱氢酶催化三羧酸循环中的限速步骤，并受到变构调节。每种同工酶为一个由两个α亚基、一个β亚基和一个γ亚基组成的异源四聚体。该基因编码的蛋白质是依赖于NAD(+)的异柠檬酸脱氢酶中的一种同工酶的α亚基。[参考资料：RefSeq，2008年7月]