亚硝基苯与还原型谷胱甘肽的反应。

Reactions of nitrosobenzene with reduced glutathione.

作者信息

Eyer P

出版信息

Chem Biol Interact. 1979 Feb;24(2):227-39. doi: 10.1016/0009-2797(79)90011-5.

Abstract

Nitrosobenzene (NOB) formed acid labile conjugates with reduced glutathione (GSH) and hemoglobin within red cells. In vitro, NOB rapidly reacted with GSH with formation of phenylhydroxylamine (PH), oxidized glutathione (GSSG), and a water-soluble compound identified as glutathionesulfinanilide (GSO-AN). Free aniline (AN), aminophenols and azoxybenzene were not detected. The proportion of PH formed increased with increasing GSH concentration and at higher pH values. Spectroscopic analysis revealed the formation of a labile adduct following a second order reaction (K = 5 x 10(3) M-1 . sec-1 at pH 7.4 and 37 degrees). This reaction was reversible because nearly all NOB could be extracted with ether from the labile intermediate. On the other hand, the labile intermediate was transformed into GSO-AN (with increasing rate at lower pH values) or it was cleaved by GSH with formation of GSSG and PH. Intermediate formation of NOB and thiol radicals was ruled out by analysis of the equilibrium data. A tentative scheme is presented for the proposed reaction mechanism.

摘要

亚硝基苯（NOB）在红细胞内与还原型谷胱甘肽（GSH）和血红蛋白形成酸不稳定共轭物。在体外，NOB与GSH迅速反应，生成苯羟胺（PH）、氧化型谷胱甘肽（GSSG）以及一种被鉴定为谷胱甘肽亚磺酰苯胺（GSO-AN）的水溶性化合物。未检测到游离苯胺（AN）、氨基酚和氧化偶氮苯。随着GSH浓度的增加以及pH值升高，生成的PH比例增加。光谱分析表明，在二级反应后形成了一种不稳定加合物（在pH 7.4和37℃时，K = 5×10³ M⁻¹·秒⁻¹）。该反应是可逆的，因为几乎所有的NOB都可以用乙醚从不稳定中间体中萃取出来。另一方面，不稳定中间体转化为GSO-AN（在较低pH值下速率增加），或者被GSH裂解，生成GSSG和PH。通过对平衡数据的分析排除了NOB和硫醇自由基的中间形成。针对提出的反应机制给出了一个初步方案。