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.

致癌和诱变的N-亚硝基二氧化氮胺存在于我们的环境中。为了研究致癌N-亚硝基胺的活化形式的生物学和化学性质，将Fenton的试剂用作细胞色素P450的替代化学模型。 Fenton的试剂含有铁盐和过氧化氢，在乙酸缓冲液中补充了铜盐（pH 4.5），已被用作替代代谢系统。在芬顿试剂存在下N-亚硝基二算胺的反应混合物的提取物在Typhimurium TA1535和E.COI WP2 UVRA中是诱变的。这是Fenton试剂将二烷基硝基胺激活到直接作用诱变剂中。源自Fenton试剂处理的N-亚硝基二烷基（NMB）的提取物在测试的N-硝基二烷基胺中的活性最高。为了鉴定从NMB衍生的直接作用诱变剂的结构，从反应混合物中分离了诱变剂，并测量了 ^H-， ^<13> c-NMR，IR和MS。直接作用诱变剂的结构最初是3-甲基-3-硝酸或硝基硫酸2-吡唑啉2-氧化物的结构，最终确定了5-甲基-5-硝基吡啶1-氧化物。使用鼠伤寒链球菌O^6-甲基鸟嘌呤甲基转移酶缺陷菌株YG7108分配了诱变剂的活性，并将结果与鼠伤寒链球菌TA1535进行了比较。鼠伤寒沙门氏菌YG7108中的诱变性增加，这表明在芬顿试剂存在下衍生自NMB的诱变性是由于DNA酗酒引起的，类似于通过α-羟基硝基胺的酒精化。