Activation mechanism of carcinogenic N-nitrosodialkyamines by chemical model for cytochrome P450

通过细胞色素P450化学模型研究致癌N-亚硝基二烷基胺的激活机制

基本信息

批准号：
11672229
负责人：
MOCHIZUKI Masataka
金额：
$ 2.3万
依托单位：
Kyoritsu University of Pharmacy
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

Carcinogenic and mutagenic N-nitrosodialkylamines exist in our environment. In order to study the biological and chemical properties of the activated form of carcinogenic N-nitrosodialkylamines, Fenton's reagent was used as an alternative chemical model for cytochrome P450. The Fenton's reagent containing an iron salt and hydrogen peroxide, supplemented with copper salts in acetate buffer (pH 4.5), has been used as an alternative metabolic system. The extract of the reaction mixture of N-nitrosodialkylamines in the presence of Fenton's reagent was mutagenic in S. typhimurium TA1535 and E.coi WP2 uvrA. Thus, the Fenton reagent activated the dialkylnitrosamines into direct-acting mutagens. The extract derived from N-nitroso-N-methylbutylamine (NMB) treated with Fenton's reagent showed the highest activity among N-nitrosodialkylamines tested. To identify structure of the direct-acting mutagen derived from NMB, the mutagen was isolated from the reaction mixture, and ^H-, ^<13>C-NMR, IR and MS were measured. The structure of the direct-acting mutagen was presumed to be 3-methyl-3-nitrito or nitro-Δ^1-pyrazoline 2-oxide originally, and 5-methyl-5-nitropyrazoline 1-oxide was finally identified. The activity of the mutagen was assayed using the S. typhimurium O^6-methylguanine methyltransferase-deficient strain YG7108, and the result was compared to that of the parent strain S. typhimurium TA1535. The mutagenicity increased in S. typhimurium YG7108, suggesting that the mutagenicity derived from NMB in the presence of the Fenton's reagent was due to DNA alkylation similar to the alkylation through α-hydroxynitrosamines.

我们的环境中存在致癌和致突变的 N-亚硝基二烷基胺，为了研究致癌性 N-亚硝基二烷基胺的活化形式的生物和化学性质，使用芬顿试剂作为含有铁盐的细胞色素 P450 的替代化学模型。和过氧化氢，在醋酸盐缓冲液（pH 4.5）中补充铜盐，已被用作替代代谢系统的提取物。 N-亚硝基二烷基胺的反应混合物在芬顿试剂存在下对鼠伤寒沙门氏菌 TA1535 和大肠杆菌 WP2 uvrA 具有诱变作用，因此，芬顿试剂将二烷基亚硝胺激活为直接作用的诱变剂。 -用芬顿试剂处理的甲基丁胺（NMB）在其中表现出最高的活性测试的N-亚硝基二烷基胺为了鉴定衍生自NMB的直接作用诱变剂的结构，从反应混合物中分离诱变剂，并测量1 H-、 13 C-NMR、IR和MS。最初被推测为3-甲基-3-亚硝基或硝基-Δ^1-吡唑啉2-氧化物，并且最后使用鼠伤寒沙门氏菌O^6-甲基鸟嘌呤甲基转移酶缺陷菌株YG7108测定了该诱变剂的活性，并将结果与亲本菌株进行了比较。鼠伤寒沙门氏菌 TA1535 的致突变性在鼠伤寒沙门氏菌 YG7108 中增加，表明致突变性源自鼠伤寒沙门氏菌 TA1535。在芬顿试剂存在下从 NMB 中产生的 DNA 烷基化类似于通过 α-羟基亚硝胺的烷基化。