ROLE OF FLAVIN-DEPENDENT MONOOXYGENASES AND CYTOCHROME-P450 ENZYMES IN THE SULFOXIDATION OF S-METHYL N,N-DIETHYLTHIOLCARBAMATE
ROLE OF FLAVIN-DEPENDENT MONOOXYGENASES AND CYTOCHROME-P450 ENZYMES IN THE SULFOXIDATION OF S-METHYL N,N-DIETHYLTHIOLCARBAMATE
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DOI：
10.1016/0006-2952(93)90620-c
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发表时间：
1993-12-14
影响因子：
5.8
通讯作者：
FAIMAN, MD
中科院分区：
文献类型：
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作者：
MADAN, A;PARKINSON, A;FAIMAN, MD
双硫仑被生物激活为 S-甲基 N,N-二乙基硫醇氨基甲酸酯亚砜 (DETC-MeSO)，该代谢物被认为是双硫仑作为乙醛脱氢酶抑制剂的作用的原因。该生物活化过程包括还原、S-甲基化和两次连续的氧化。含硫官能团是细胞色素 P450 酶或含黄素单加氧酶 (FMO) 的底物。在本研究中，我们研究了这些单加氧酶对从其直接前体 S-甲基 N,N-二乙基硫醇氨基甲酸酯 (DETC-Me) 形成 DETC-MeSO 的贡献。从成熟雄性大鼠获得的肝微粒体与 DETC-Me 一起孵育。 DETC-MeSO 的形成被去垢剂 Emulgen 911 溶解微粒体或细胞色素 P450 抑制剂 1-苯甲基咪唑的存在所完全阻断。然而，FMO 的热失活仅导致 DETC-MeSO 形成的部分损失。与对照组相比，苯巴比妥治疗大鼠的肝微粒体中 DETC-MeSO 的形成率增加了 4 至 5 倍。与对照组相比，吡唑治疗大鼠的肝微粒体显示 DETC-Me 磺化氧化减少了 50%。在纯化的重构系统中，细胞色素 P450 2B1 (CYP2B1) 以 51 nmol DETC-MeSO 形成/分钟/nmol 细胞色素 P450 的速率催化 DETC-MeSO 的形成。 CYP2B1 抗体引起苯巴比妥治疗大鼠肝微粒体 DETC-MeSO 形成的 60% 抑制。这些结果表明，在雄性大鼠五微粒体中，细胞色素 P450 在催化 DETC-Me 磺化氧化中起主要作用，而 FMO 起次要作用（
Disulfiram is bioactivated to S-methyl N,N-diethylthiolcarbamate sulfoxide (DETC-MeSO), the metabolite proposed to be responsible for the action of disulfiram as an aldehyde dehydrogenase inhibitor. This bioactivation process includes a reduction, an S-methylation, and two successive oxidations. Sulfur-containing functional groups are substrates for cytochrome P450 enzymes or flavin-containing monooxygenases (FMO). In the present study, we investigated the contribution of these monooxygenases to the formation of DETC-MeSO from its immediate precursor S-methyl N,N-diethylthiolcarbamate (DETC-Me). Liver microsomes obtained from mature male rats were incubated with DETC-Me. The formation of DETC-MeSO was blocked completely by solubilization of the microsomes with the detergent Emulgen 911, or by the presence of the cytochrome P450 inhibitor 1-benzylimidazole, However, thermal-inactivation of FMO resulted in only a partial loss in DETC-MeSO formation. Liver microsomes from phenobarbital-treated rats showed a 4- to 5-fold increase in the rate of formation of DETC-MeSO, compared with controls. Liver microsomes from pyrazole-treated rats showed a 50% decrease in the sulfoxidation of DETC-Me compared with controls. In a purified reconstituted system, cytochrome P450 2B1 (CYP2B1) catalyzed the formation of DETC-MeSO at a rate of 51 nmol DETC-MeSO formed/min/nmol cytochrome P450. Antibodies to CYP2B1 caused a 60% inhibition of DETC-MeSO formation by liver microsomes from phenobarbital-treated rats. These results suggest that in male rat fiver microsomes, cytochrome P450 plays a major role in catalyzing the sulfoxidation of DETC-Me, whereas FMO plays a minor role (