作者:Goutam Chowdhury、M. Wade Calcutt、Leslie D. Nagy、F. Peter Guengerich
DOI:10.1021/bi301092c
日期:2012.12.18
No kinetic lags were observed in acid formation; pulse–chase experiments with carrier aldehydes showed only limited equilibration with P450 2E1-bound aldehydes, indicative of processive reactions, as reported for P450 2A6 [Chowdhury, G., et al. (2010) J. Biol. Chem. 285, 8031–8044]. These same features (no lag phase for HCO2H formation and a lack of equilibration in pulse–chase assays) were also seen
细胞色素 P450 (P450) 2E1 是氧化N-亚硝基二甲胺[ N , N-二甲基亚硝胺 (DMN)]的主要酶,N-亚硝基二甲胺是一种致癌物质,也是一些内源性亚硝胺的代表。大鼠或人 P450 2E1 将 DMN 氧化为 HCHO 显示出高表观的固有动力学氘同位素效应 (KIE),≥8。的KIE没有与大鼠肝微粒非竞争性分子间实验减毒d V = 12.5; D ( V / K ) = 10.9 [Northrop 的命名法,DB (1982) Methods Enzymol。87 , 607–625]} 但与纯化的人 P450 2E1 [ D V = 3.3; D( V / K ) = 3.7],表明 C-H 键断裂对人类 P450 2E1 有部分限速作用。使用N-亚硝基二乙胺[ N , N-二乙基亚硝胺 (DEN)],内在 KIE 略低,并且在非竞争性分子间实验中未表达 [例如,D (