Reconstitution of C27-steroid 26-hydroxylase activity from bovine brain mitochondria.
We have previously demonstrated the presence of cytochrome P-450 in a soluble preparation of bovine brain mitochondria (Oftebro, H., Størmer, F.C., and Pedersen, J.I. (1979) J. Biol. Chem. 254, 4331). In the present work we show that this preparation, in the presence of NADPH, adrenodoxin and adrenodoxin reductase catalyzes omega-hydroxylation of a number of C27-steroids that are intermediates in bile acid biosynthesis. The rates of hydroxylation were 1-2 order of magnitudes lower than reported for similar preparations from rat and human liver. No significant activity was detected with cholesterol as substrate. The physiological significance of brain mitochondrial cytochrome P-450 is discussed.
Institute for Nutrition Research, School of Medicine, University of Oslo, Norway.
J I
JI
Pedersen
H
H
Oftebro
I
I
Björkhem
D000325:Adrenodoxin / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000201:enzymology*; D001923:Brain Chemistry; D002417:Cattle; D053493:Cholestanetriol 26-Monooxygenase; D002851:Chromatography, High Pressure Liquid; D003577:Cytochrome P-450 Enzyme System / Q000302:isolation & purification* / Q000378:metabolism; D005287:Ferredoxin-NADP Reductase / Q000378:metabolism; D006801:Humans; D006900:Hydroxylation; D008099:Liver / Q000201:enzymology; D008928:Mitochondria / Q000201:enzymology*; D009249:NADP / Q000378:metabolism; D051381:Rats; D013250:Steroid Hydroxylases / Q000302:isolation & purification*; D013379:Substrate Specificity
D000325:Adrenodoxin; D009249:NADP; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; C506831:CYP27A1 protein, human; D053493:Cholestanetriol 26-Monooxygenase; D005287:Ferredoxin-NADP Reductase