title: Evidence for the formation of 26-hydroxycholesterol by cytochrome P-450 in pig kidney mitochondria.
abstract: Pig kidney mitochondria were found to catalyze the formation of 26-hydroxycholesterol, an inhibitor of cholesterol biosynthesis. The cholesterol 26-hydroxylase was purified 600-fold. It was present in a mitochondrial enzyme fraction enriched in cytochrome P-450. The cytochrome P-450 fraction required NADPH, mitochondrial ferredoxin and ferredoxin reductase for 26-hydroxylase activity. The mitochondria and the purified 26-hydroxylase preparation also catalyzed 26-hydroxylation of 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol, and intermediate in cholic acid biosynthesis, and of 25-hydroxyvitamin D3. The role of extra-hepatic formation of 26-hydroxycholesterol is discussed.
authors.affiliation: Department of Pharmaceutical Biochemistry, University of Uppsala, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Postlind
authors.forename: K
authors.initials: K
authors.lastname: Wikvall
mesh_terms: D000818:Animals; D053493:Cholestanetriol 26-Monooxygenase; D003577:Cytochrome P-450 Enzyme System / Q000302:isolation & purification / Q000378:metabolism*; D006888:Hydroxycholesterols / Q000096:biosynthesis*; D007668:Kidney / Q000201:enzymology*; D008928:Mitochondria / Q000201:enzymology*; D013250:Steroid Hydroxylases / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity; D013552:Swine
chemical_list: D006888:Hydroxycholesterols; C007042:cholest-5-ene-3 beta,26-diol; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D053493:Cholestanetriol 26-Monooxygenase