论文部分内容阅读
目的 探讨细胞色素P450加单氧酶系以外的代谢途径对杀虫剂的脱烷基作用 ,检测脂氧合酶 (LOX)介导的灭害威等的N 位脱甲基作用。方法 通过Nash反应检测大豆脂氧合酶 (SLO)对灭害威作用产生甲醛的量 ,反映其介导杀虫剂的N 位脱甲基反应速率。结果 SLO对灭害威的脱甲基作用与反应时间以及SLO浓度、灭害威和过氧化氢的浓度呈依赖关系。在最佳反应条件下 ,SLO产生甲醛的最大反应速度 (Vmax)为 1 8nmol·min- 1 ·nmol- 1 。SLO对灭害威的米氏常数 (Km)值为 3 .4mmol/L ,对过氧化氢的Km值为 2 35μmol/L。去甲二氢愈创木酸 (NDGA)、棉子醇 (gossypol)和芬宁东(phenidone)对脱甲基反应的强烈抑制作用提示 ,SLO起催化作用。还原型谷胱甘肽 (GSH)或二硫苏糖醇参与反应时 ,甲醛的累积量明显降低 ,表明SLO对灭害威脱甲基作用时 ,产生自由基。丁羟基甲苯(BHT)和丁羧基苯甲醚 (BHA)对甲醛的产生的抑制作用进一步支持这一论点。除灭害威外 ,发现其他的杀虫剂也发生N 位脱甲基作用 ,只是相对反应速率较低。结论 一些杀虫剂在动植物体内可能通过LOX介导发生脱烷基作用
Objective To investigate the dealkylation of insecticides by metabolic pathways other than cytochrome P450 monooxygenase and to detect the demethylation of N at lipoxygenase (LOX) mediated killing. Methods The amount of formaldehyde produced by soy lipoxygenase (SLO) against the action of damaging agents was measured by Nash reaction, which reflects the N-demethylation rate of insecticides. Results The demethylation effect of SLO on exenatide was dependent on the reaction time and the concentrations of SLO, exenatide and hydrogen peroxide. Under the optimal reaction conditions, the maximum reaction rate (Vmax) of SLO to produce formaldehyde was 18 nmol · min-1 · nmol-1. The Michaelis constant (Km) value of SLO for exenatide was 3.4 mmol / L and the Km value for hydrogen peroxide was 235 micromol / L. Strong inhibition of demethylation by nordihydroguaiaretic acid (NDGA), gossypol and phenidone suggests that SLO acts as a catalyst. Reduced glutathione (GSH) or dithiothreitol involved in the reaction, the cumulative amount of formaldehyde was significantly reduced, indicating that the offensive role of SLO on the demethylation of free radicals. The inhibition of the formaldehyde production by butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) further supports this argument. In addition to exterminating damaging agents, other insecticides were also found to undergo N-demethylation at relatively low relative rates of reaction. Conclusion Some pesticides may be dealkylated by LOX in animals and plants