高等植物中的谷氨酸脱氢酶及其生理作用

谷氨酸脱氢酶普遍存在于植物体内，它虽然不是植物吸收利用氮素的主要成员，但在植物氮代谢中起着重要作用。高等植物的谷氨酸脱氢酶主要存在于线粒体中，以烟酰胺腺嘌呤二核苷酸（NADH)为辅酶。该酶分子量为255-258kD,由六个亚基组成，亚基包括a和b两种类型，存在七种同工酶形式。又能氧化脱铵从而为三羧酸循环提供碳骨架。

The Physiological Role of Glutamate Dehydrogenase in Higher Plants

Glutamate dehydrogenase(GDH) is present mainly in mitochondria in higher plants and catalyses both the amination of a-oxoglutamate, with NADH as the electron donor, and the deamination of glutamate to ammonia and a-oxoglutamate, with NAD+ as the electron receptor. The NAD (H)-GDH, with a molecular weight of 255-258kD, is composed of six subunits of a and b in different ratios to form seven isoenzymes. The enzyme seems to function in assimilation of ammonia under stress conditions such as high temperature, in senescence and other abnormalities. It also functions in higher plants to direct carbon skeletons into the citric acid cycle under conditions of carbon stress.