六种大鼠肝微粒体细胞色素P450重组酶系对33种外来化合物的代谢

Metabolism of 33 xenobiotics by six reconstituted microsomal cytochrome P450 enzyme systems purifiedfrom rat liver

多氯联苯诱导的六种鼠肝微粒体细胞色素P450重组酶系A_1,A_2,B,C_1,C_2和D对33种外来化合物代谢的催化速率不同,其中以C_1酶系和C_2酶系催化活力最强,其次为A_1酶系,B酶系催化活力最弱,外来化合物的种类不同,经重组酶系催化的途径也不同,如卤代烷烃,卤代烯烃,苯及其同系物,亚硝胺类等化合物主要经P450C_1酶系代谢,而大多数有机磷酸酯,氨基甲酸酯类化合物及多环芳烃类致癌物则以P450 C_2酶系代谢为主。

The results indicate that the six isoenzymes (cytochrome P450 A1 P450 A2, P450 B, P450 C1, P450 C2 and P450 D) catalyzed the oxidation of these compounds at a comparative rate. The most efficient catalysts among the six isoenzymes were P450 C1 and P450 C2 (P448) which showed the differences between their metabolic profiles on these compounds. The P450 C1 exhibited much higher catalytic activities on most smaller compounds such as halomethane,haloethylene, benzene, toluene, phenobarbital, dicyclohexylcarbodumide and nitrosamines etc. compared with P450 C2 which mainly catalyzed organophosphorus compounds, carbaryl, TOCP and polycyclic aromatic hydrocarbons.