Schasteen C S, Curthoys N P, Reed D J
Biochem Biophys Res Commun. 1983 Apr 29;112(2):564-70. doi: 10.1016/0006-291x(83)91501-2.
The glutathione-protein binding interactions of rat renal gamma-glutamyltransferase (gamma GT) were studied by examining the effect of phenylglyoxal (PGO), a chemical modifying agent for arginyl residues. PGO inactivation of gamma GT followed pseudo-first order kinetics and the rate was dependent upon the concentration of PGO. Glutathione (GSH) protected the enzyme from inactivation by PGO. The anti-tumor drug L-(alpha S, 5S)-alpha-amino-3-chloro-4,5-dihydro-5-isoxazoleacetic acid (AT-125) inactivated purified gamma GT. The inactivation capability of AT-125 was abolished by esterification of the carboxyl moiety and was regained upon incubation of AT-125 methyl ester with a carboxyl esterase. AT-125 and glutathione may bind to gamma GT via the electrostatic interaction of their respective carboxyl group(s) and an arginyl residue at the active site.
通过研究精氨酰残基化学修饰剂苯乙二醛（PGO）的作用，对大鼠肾γ-谷氨酰转移酶（γGT）的谷胱甘肽-蛋白质结合相互作用进行了研究。γGT的PGO失活遵循假一级动力学，其速率取决于PGO的浓度。谷胱甘肽（GSH）保护该酶不被PGO失活。抗肿瘤药物L-(αS,5S)-α-氨基-3-氯-4,5-二氢-5-异恶唑乙酸（AT-125）使纯化的γGT失活。AT-125的羧基部分酯化后，其失活能力消失，而将AT-125甲酯与羧基酯酶一起孵育后，其失活能力又恢复。AT-125和谷胱甘肽可能通过它们各自羧基与活性位点精氨酰残基的静电相互作用而与γGT结合。
