细胞色素P450抑制剂对白腐菌Phlebia lindtneri降解氯丹的影响

Effects of cytochrome P450 inhibitors on the biotransformation of chlordane by white-rot fungus Phlebia lindtneri

为确定细胞色素P450酶系在白腐菌Phlebia lindtneri降解有机氯类农药氯丹中的作用,在液体培养条件下,以胡椒基丁醚和1-氨基苯并三唑作为细胞色素P450的抑制剂,分析了不同浓度抑制剂对氯丹的降解、代谢产物的生成以及中间代谢物降解的影响。结果表明:与对照相比,高浓度(1.0 mmol/L)胡椒基丁醚或1-氨基苯并三唑处理15 d后氯丹的降解率均下降了约60%,且其代谢产物中除七氯和二氯代六氯的检出量显著增加外,其余环氧化及羟基化代谢产物均未检出;此外,添加高浓度的抑制剂可导致白腐菌降解中间代谢产物七氯及二氯代六氯的降解率下降90%以上,氧化氯丹的降解率下降70%以上,但不影响环氧七氯的降解。表明细胞色素P450可能是氯丹降解的主要酶系,其参与催化了氯丹的初始羟基化和水解、七氯和二氯代六氯的环氧化及氧化氯丹的水解等多个反应过程。

The effects of cytochrome P450 inhibitors on biotransformation of organochlorine pesticide chlordane by white-rot fungus Phlebia lindtneri during 15 days of incubation was investigated using piperonyl butoxide （PBO） and 1-aminobenzotriazole（ABT）. In contrast to the degradation of chlordane in cultures without inhibitors, degradation of chlordane was inhibited at a rate of about 60% in cultures with 1.0 mmol/L PBO or ABT, and the accumulation of most metabolites clearly decreased, except heptachlor and dichlorochlordene, which showed a markedly increase in cultures with inhibitors. Moreover, PBO and ABT efficiently inhibited degradation of the metabolites of chlordane, heptachlor, dichlorochlordene and oxychlordane, but had no effect on degradation of heptachlor epoxide. These results indicated that fungal cytochrome P450 enzymes involved in some steps of chlordane transformation, especially in the hydroxylation, epoxidation and hydrolysis process.