Participation of the Microsomal Electron Transport System Involving Cytochrome P-450 in 7a-Hydroxylation of Cholesterol

Abstract
The participation of the microsomal electron transport system involving cytochrome P-450 in 7α-hydroxylation of cholesterol by a rat liver preparation was examined since this process involves microsomal reactions requiring both NADPH and molecular oxygen. 7α-Hydroxylation of cholesterol was inhibited by carbon monoxide and by antibody against NADPH-cytochrome c reductase. The 7α-hydroxylase activity of liver microsomes in animals under various conditions varied but variation was not in parallel with variation in the microsomal cytochrome P-450 content. It is concluded that the microsomal electron transport system, involving cytochrome P-450, functions in 7α-hydroxylation of cholesterol. The existence of a specific cytochrome P-450 for 7α-hydroxylation, i.e., multiplicity of cytochrome P-450, is suggested.

This publication has 0 references indexed in Scilit: