Kondo T, Taniguchi N, Kawakami Y
Eur J Biochem. 1984 Nov 15;145(1):131-6. doi: 10.1111/j.1432-1033.1984.tb08531.x.
The significance of glutathione S-conjugate in the regulation of glutathione synthesis was studied using human erythrocyte gamma-glutamylcysteine synthetase. Feedback inhibition of the enzyme by reduced glutathione was released by the addition of the glutathione S-conjugate (S-2,4-dinitrophenyl glutathione). A half-maximal effect of glutathione S-conjugate on gamma-glutamylcysteine synthetase activity was obtained at approximately 1 microM; 50 microM glutathione S-conjugate in the presence of 10 mM glutathione actually increased the enzyme activity twofold above uninhibited levels. Glutathione S-conjugate had no effect on the enzyme activity in the absence of glutathione. When erythrocytes were exposed to the electrophile 1-chloro-2,4-dinitrobenzene, which forms a glutathione S-conjugate by the catalytic reaction of glutathione S-transferase, the level of glutathione synthesis increased. These data suggest that glutathione S-conjugate plays a role in stimulating the synthesis of glutathione.
利用人红细胞γ-谷氨酰半胱氨酸合成酶研究了谷胱甘肽S-共轭物在谷胱甘肽合成调节中的意义。添加谷胱甘肽S-共轭物（S-2,4-二硝基苯基谷胱甘肽）可解除还原型谷胱甘肽对该酶的反馈抑制。谷胱甘肽S-共轭物对γ-谷氨酰半胱氨酸合成酶活性的半数最大效应在约1微摩尔时获得；在10毫摩尔谷胱甘肽存在下，50微摩尔谷胱甘肽S-共轭物实际上使酶活性比未受抑制水平提高了两倍。在没有谷胱甘肽的情况下，谷胱甘肽S-共轭物对酶活性没有影响。当红细胞暴露于亲电试剂1-氯-2,4-二硝基苯时，该亲电试剂通过谷胱甘肽S-转移酶的催化反应形成谷胱甘肽S-共轭物，谷胱甘肽合成水平增加。这些数据表明谷胱甘肽S-共轭物在刺激谷胱甘肽合成中起作用。
