Kortenkamp A, Oetken G, Beyersmann D
University of Bremen, Department of Biology and Chemistry, F.R.G.
Mutat Res. 1990 Oct;232(2):155-61. doi: 10.1016/0027-5107(90)90120-s.
The number of strand breaks induced by the combination of chromate and glutathione (GSH) in PM2 DNA was effectively reduced upon addition of the hydroxyl radical scavengers dimethyl sulphoxide (DMSO), formate and benzoate. Administration of catalase also led to a depression of DNA degradation whereas superoxide dismutase (SOD) had very little influence. Essentially the same results were obtained in experiments employing a chromium(V) complex Na4(GSH)4Cr.8H20, which is an intermediate chromium species isolated from the reduction of chromate by glutathione. DNA cleavage was dependent on the presence of iron (FeCl3). When compared with the number of breaks produced by FeCl3 and GSH alone, chromate stimulated the generation of single-strand breaks. These findings suggest that hydroxyl radicals are one ultimate DNA cleaving agent in both reactions. A reaction scheme for the production of hydroxyl radicals is proposed.
在PM2 DNA中，当加入羟基自由基清除剂二甲基亚砜（DMSO）、甲酸盐和苯甲酸盐时，铬酸盐与谷胱甘肽（GSH）联合诱导产生的链断裂数量有效减少。过氧化氢酶的施用也导致DNA降解减少，而超氧化物歧化酶（SOD）的影响很小。在使用铬（V）配合物Na4（GSH）4Cr·8H2O进行的实验中获得了基本相同的结果，该配合物是从谷胱甘肽还原铬酸盐过程中分离出的一种中间铬物种。DNA切割依赖于铁（FeCl3）的存在。与单独由FeCl3和GSH产生的断裂数量相比，铬酸盐刺激了单链断裂的产生。这些发现表明，羟基自由基是这两种反应中最终的DNA切割剂之一。本文提出了一个产生羟基自由基的反应方案。
