大鼠组织中γ-谷氨酰异羟肟酸合成酶与L-谷氨酰胺-羟胺谷氨酰转移酶活性的区别。
The distinction between gamma-glutamylhydroxamate synthetase and L-glutamine-hydroxylamine glutamyltransferase activities in rat tissues.
作者信息
Herzfeld A, Estes N A
出版信息
Biochem J. 1973 May;133(1):59-66. doi: 10.1042/bj1330059.
The formation of gamma-glutamylhydroxamate by homogenates under optimum assay condition showed an inconstancy in the ratios of the enzyme activities utilizing l-glutamate and ATP (gamma-glutamylhydroxamate synthetase) and l-glutamine and ADP (l-glutamine-hydroxylamine glutamyltransferase) in a number of normal and neoplastic rat tissues. Although gamma-glutamylhydroxamate synthetase activities in adult livers and kidneys were identical in males and females, l-glutamine-hydroxylamine glutamyltransferase activities in the organs of females were significantly lower. The developmental formations of the two activities in liver, kidney, brain and muscle were not simultaneous. The l-glutamine-hydroxylamine glutamyltransferase activity in foetal liver or neonatal kidney could be prematurely evoked by thyroxine, but the gamma-glutamylhydroxamate synthetase activity remained unchanged. Injections of cortisol also had dissimilar effects on the two activities in thymus and hepatomas. The discrepant tissue distribution, asynchronous developmental formation and differential response to several hormonal stimuli provide evidence in vivo that the two activities are not catalysed by the same protein.
在最佳测定条件下，匀浆物生成γ-谷氨酰异羟肟酸的过程显示，在许多正常和肿瘤大鼠组织中，利用L-谷氨酸和ATP（γ-谷氨酰异羟肟酸合成酶）以及L-谷氨酰胺和ADP（L-谷氨酰胺-羟胺谷氨酰转移酶）的酶活性比率不稳定。尽管成年肝脏和肾脏中γ-谷氨酰异羟肟酸合成酶活性在雄性和雌性中相同，但雌性器官中L-谷氨酰胺-羟胺谷氨酰转移酶活性显著较低。肝脏、肾脏、大脑和肌肉中这两种活性的发育形成并不同步。胎儿肝脏或新生肾脏中的L-谷氨酰胺-羟胺谷氨酰转移酶活性可被甲状腺素过早诱导，但γ-谷氨酰异羟肟酸合成酶活性保持不变。注射皮质醇对胸腺和肝癌中的这两种活性也有不同影响。组织分布的差异、发育形成的不同步以及对几种激素刺激的不同反应，在体内证明了这两种活性并非由同一种蛋白质催化。
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