Dierickx P J
Pharmacol Res Commun. 1983 Jun;15(6):581-91. doi: 10.1016/s0031-6989(83)80029-0.
The in vitro interaction of 1,4-benzoquinone, 1,2- and 1,4-naphthoquinone, and 2-methyl-1,4-naphthoquinone with rat liver glutathione S-transferases (GST) was studied, using reduced glutathione and 1-chloro-2,4-dinitrobenzene (CDNB) as substrates. The inhibition of the GST activity by quinones in crude extracts was dose dependent. While most of the dihydroxynaphtalenes investigated also inhibited the GST activity, dihydroxybenzenes and catecholamines did not. The quinones inhibited all the GST isoenzymes, albeit at different degrees. Kinetic studies revealed mixed type function inhibition towards glutathione and competitive inhibition towards CDNB, implicating that quinones are GST substrates. This was further confirmed by titration of remaining glutathione in appropriate incubation mixtures. These results indicate that GST could have a protective function against quinones, and that catecholamines are conjugated with glutathione via a reactive quinone intermediate.
以还原型谷胱甘肽和1-氯-2,4-二硝基苯（CDNB）为底物，研究了1,4-苯醌、1,2-萘醌和1,4-萘醌以及2-甲基-1,4-萘醌与大鼠肝脏谷胱甘肽S-转移酶（GST）的体外相互作用。醌类物质对粗提物中GST活性的抑制作用呈剂量依赖性。虽然所研究的大多数二羟基萘也抑制GST活性，但二羟基苯和儿茶酚胺则不然。醌类物质抑制了所有的GST同工酶，尽管程度不同。动力学研究表明，醌类物质对谷胱甘肽具有混合型功能抑制作用，对CDNB具有竞争性抑制作用，这表明醌类物质是GST的底物。通过滴定适当孵育混合物中剩余的谷胱甘肽，进一步证实了这一点。这些结果表明，GST可能对醌类物质具有保护作用，并且儿茶酚胺通过反应性醌中间体与谷胱甘肽结合。
