Keen J H, Jakoby W B
J Biol Chem. 1978 Aug 25;253(16):5654-7.
Homogeneous preparations of the glutathione transferases from rat liver have been tested for their ability to catalyze a number of diverse nucleophilic reactions of GSH. Although disulfide interchange with GSSG or L-cystine, and cis-trans isomerization of maleic acid, are clearly promoted by thiols in solution, the reactions were not catalyzed by the glutathione transferases. In contrast, certain more hydrophobic analogs of these compounds were found to serve as substrates. The transferases also catalyze the glutathione-dependent release of p-nitrophenol from p-nitrophenyl acetate and p-nitrophenyl trimethylacetate. These observations are consistent with the formulation that catalysis may result from close juxtaposition of sufficiently electrophilic, nonpolar compounds with GSH on the enzyme surface.
已对来自大鼠肝脏的谷胱甘肽转移酶的均一制剂催化谷胱甘肽（GSH）多种不同亲核反应的能力进行了测试。尽管溶液中的硫醇能明显促进与氧化型谷胱甘肽（GSSG）或L-胱氨酸的二硫键交换以及马来酸的顺反异构化，但这些反应并未由谷胱甘肽转移酶催化。相比之下，发现这些化合物的某些疏水性更强的类似物可作为底物。这些转移酶还催化从对硝基苯乙酸酯和对硝基苯三甲基乙酸酯中以谷胱甘肽依赖性方式释放对硝基苯酚。这些观察结果与以下表述一致：催化作用可能是由于酶表面上具有足够亲电性的非极性化合物与谷胱甘肽紧密并置所致。
