TYROSINE-7 IN HUMAN CLASS-PI GLUTATHIONE-S-TRANSFERASE IS IMPORTANT FOR LOWERING THE PKA OF THE THIOL-GROUP OF GLUTATHIONE IN THE ENZYME-GLUTATHIONE COMPLEX

被引：64

作者：

KONG, KH ^{[1
]}

TAKASU, K ^{[1
]}

INOUE, H ^{[1
]}

TAKAHASHI, K ^{[1
]}

机构：

[1] UNIV TOKYO,FAC SCI,DEPT BIOPHYS & BIOCHEM,BUNKYO KU,TOKYO 113,JAPAN

来源：

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS | 1992年 / 184卷 / 01期

关键词：

D O I：

10.1016/0006-291X(92)91177-R

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Previously, we reported the importance of Tyr7 for the catalytic activity of human class Pi glutathione S-transferase [Kong et al. (1992) Biochem. Biophys. Res. Comm., 182, 1122]. As an extention of this study, we investigated the pH dependence of kinetic parameters of the wild-type enzyme and the Y7F mutant. The replacement of Tyr7 with phenylalanine was found to alter the pH dependence of Vmax and Vmax KmCDNB of the enzyme for conjugation of GSH with 1-chloro-2,4-dinitrobenzene (CDNB). The pKa of the thiol of GSH in the wild-type enzyme-GSH complex was estimated to be about 2.4 pK units lower than that in the Y7F-GSH complex. Tyr7 is thus considered to be important for catalytic activity in lowering the pKa of the thiol of GSH in the enzyme-GSH complex. © 1992.

引用

页码：194 / 197

页数：4

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