Stereochemical Course of the Biotransformation of Isoprene Monoepoxides and of the Corresponding Diols with Liver Microsomes from Control and Induced Rats
作者:Cinzia Chiappe、Antonietta De Rubertis、Viola Tinagli、Giada Amato、Pier Giovanni Gervasi
DOI:10.1021/tx000061a
日期:2000.9.1
by liver enzymes from control and induced rats has been determined. Between the two primarily formed metabolites, 2-methyl-2-vinyloxirane (2) and isopropenyloxirane (3), epoxide 2 is rapidly transformed into the corresponding vicinal racemic diol 4, predominantly through a nonenzymatic hydrolysis reaction. At variance, epoxide 3 is mainly biotransformed into the diol 5 by microsomal epoxide hydrolase
已经确定了来自对照和诱导大鼠的肝酶对异戊二烯进行生物转化的立体化学过程。在两个主要形成的代谢物2-甲基-2-乙烯基环氧乙烷(2)和异丙烯基环氧乙烷(3)之间,环氧化物2主要通过非酶水解反应迅速转变为相应的邻位外消旋二醇4。在不同的情况下,环氧化物3主要通过微粒体环氧化物水解酶(mEH)生物转化为二醇5,以在50%转化率之前选择性地生成(R)-3-甲基-3-丁烯-1,2-二醇5。与单环氧化物3氧化成相应的二环氧化物6竞争。P450催化的3的环氧化的特征在于中等的立体选择性,然而,立体选择性强烈地依赖于P450的诱导。用苯巴比妥(PB)(P450 2B1和3A的诱导剂)治疗大鼠可产生高选择性苏-(2R,2'R)-6,而用吡唑(Pyr)(P450 2E1的诱导剂)处理,有利于同时形成赤型-(2S,2'R)-和苏型-(2R,2'R)-6。mEH催化的双环氧化物6的水解进行,尽管具有适度的周转率,但