Sulfoxidation of Mercapturic Acids Derived from Tri- and Tetrachloroethene by Cytochromes P450 3A: A Bioactivation Reaction in Addition to Deacetylation and Cysteine Conjugate β-Lyase Mediated Cleavage
作者:Michael Werner、Gerhard Birner、Wolfgang Dekant
DOI:10.1021/tx950075u
日期:1996.1.1
2-DCVC are oxidized to the corresponding sulfoxides mainly, if not exclusively, by cytochrome P450 enzymes in liver microsomes of untreated male rats, since no role for the flavin-containing monooxygenase (FMO) could be demonstrated by heat inactivation experiments and by the use of n-octylamine. The sulfoxidation rates were increased when using liver microsomes of phenobarbital and dexamethasone pretreated
在本研究中,我们调查了由N-乙酰基-S-(1,2,2-三氯乙烯基)-L-半胱氨酸(N-Ac-TCVC),N-乙酰基-S-(1,2-二氯乙烯基)形成亚砜的情况)-L-半胱氨酸(N-Ac-1,2-DCVC)和N-乙酰基-S-(2,2-二氯乙烯基)-L-半胱氨酸(N-Ac-2,2-DCVC)谷胱甘肽对三氯乙烯和四氯乙烯的生物活化作用。第一个目的是阐明与这些氧化反应有关的酶。N-Ac-TCVC,N-Ac-1,2-DCVC和N-Ac-2,2-DCVC主要(如果非排他性地)被未经处理的雄性大鼠肝微粒体中的细胞色素P450酶氧化为相应的亚砜,因为通过热灭活实验和使用正辛胺无法证明含黄素的单加氧酶(FMO)的作用。当使用苯巴比妥和地塞米松预处理的雄性大鼠的肝微粒体以及地塞米松预处理的雌性大鼠的肝微粒体时,亚砜氧化速率增加,而未处理的雌性大鼠的肝微粒体中未观察到亚砜形成,表明细胞色素P450 3A参与其中。此外,曲雷霉素,一种细胞色素P450