摘要
谷氨酸脱氨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内 ,以烟酰胺腺嘌呤二核苷酸 (NADH)为辅酶。该酶分子量为 2 5 5～ 2 5 8kD ,由六个亚基组成 ,亚基包括α和 β两种类型 ,存在七种同工酶形式。它在植物的衰老过程及逆境如高温和水份胁迫等状况下行使其铵同化功能 ,但在黑暗或碳胁条件下又能氧化脱铵从而为三羧酸循环提供碳骨架。
Glutamate dehydrogenase(GDH)is present mainly in mitochondria in higher plants and catalyses both the amination of α-oxoglutamate,with NADH as the electron donor,and the deamination of glutamate to ammonia and α-oxoglutamate,with NAD\++ as the electron recepter.The NAD(H)-GDH,with a molecular weight of 255～258kD,is composed of six subunits of α and β 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.
出处
《植物学通报》
CSCD
北大核心
2001年第4期396-401,共6页
Chinese Bulletin of Botany
关键词
谷氨酸脱氨酶
高等植物
固液
脱铵
生理作用
NAD(H)-glutamate dehydrogenase,Higher plants,Amination,Deamination
