Principato G B, Danielson U H, Mannervik B
Department of Biochemistry, University of Stockholm, Sweden.
FEBS Lett. 1988 Apr 11;231(1):155-8. doi: 10.1016/0014-5793(88)80722-1.
Rat glutathione transferase 4-4 catalyzed the conjugation of 2-mercaptoethanol with 1-chloro-2,4-dinitrobenzene in the presence of S-methyl-glutathione. The reaction was linearly dependent on enzyme concentration and saturation was seen with respect to both 2-mercaptoethanol and S-methyl-glutathione concentration. High concentrations of S-methyl-glutathione were inhibitory. The results suggest that the natural substrate glutathione has two distinct functions in the normal catalytic reaction, (i) induction of a catalytically competent conformation of the enzyme and (ii) provision of the substrate sulfhydryl group in the reaction catalyzed.
在S-甲基谷胱甘肽存在的情况下，大鼠谷胱甘肽转移酶4-4催化2-巯基乙醇与1-氯-2,4-二硝基苯的结合反应。该反应与酶浓度呈线性相关，并且在2-巯基乙醇和S-甲基谷胱甘肽浓度方面均呈现饱和现象。高浓度的S-甲基谷胱甘肽具有抑制作用。结果表明，天然底物谷胱甘肽在正常催化反应中具有两种不同的功能：(i)诱导酶的具有催化活性的构象；(ii)在催化的反应中提供底物巯基。
