还原型辅酶Ⅱ-细胞色素P-450还原酶不是肝脏微粒体类固醇5-α还原酶的组成成分。

NADPH-cytochrome P-450 reductase is not a component of the liver microsomal steroid 5-alpha reductase.

作者信息

Cheng K C, Wang R W, Lu A Y

机构信息

Dept. Pediatrics, Cornell University Medical College, NY, NY 10021.

出版信息

Biochem Biophys Res Commun. 1989 Dec 15;165(2):590-4. doi: 10.1016/s0006-291x(89)80007-5.

DOI:10.1016/s0006-291x(89)80007-5

PMID:2512918

Abstract

Liver microsomal steroid 5-alpha-reduction is catalyzed by a NADPH-dependent enzyme system. The requirement of NADPH-cytochrome P-450 reductase to shuttle reduction equivalents from NADPH to steroid 5-alpha-reductase was investigated using an inhibitory antibody against NADPH-cytochrome P-450 reductase. This antibody preparation inhibited cytochrome c reduction in microsomes from female rat liver with an I50 of 0.75 mg antibody/mg of microsomal protein. Benzphetamine N-demethylation and testosterone 6-beta-hydroxylation, two cytochrome P-450-mediated oxidative reactions, were inhibited by the antibody. On the other hand, testosterone 5-alpha-reductase was not affected by the antibody. These results suggest that NADPH-cytochrome P-450 reductase is not an obligatory component of the liver microsomal steroid 5-alpha-reduction.

摘要

肝脏微粒体类固醇5-α还原由一种依赖NADPH的酶系统催化。使用针对NADPH-细胞色素P-450还原酶的抑制性抗体，研究了NADPH-细胞色素P-450还原酶将还原当量从NADPH穿梭至类固醇5-α还原酶的必要性。该抗体制剂抑制了雌性大鼠肝脏微粒体中的细胞色素c还原，半数抑制浓度（I50）为0.75毫克抗体/毫克微粒体蛋白。苯丙胺N-脱甲基化和睾酮6-β羟基化这两种细胞色素P-450介导的氧化反应受到该抗体的抑制。另一方面，睾酮5-α还原酶不受该抗体影响。这些结果表明，NADPH-细胞色素P-450还原酶不是肝脏微粒体类固醇5-α还原的必需成分。