title: The substrate for cholesterol 7alpha-hydroxylase.
abstract: The rates of incorporation of (14C) cholesterol into cholesteryl esters and 5-cholestene-3beta,7alpha-diol (7alpha-hydroxycholesterol) by rat liver microsomes, measured under conditions in which esterification and 7alpha-hydroxylation are varied independently, indicated that cholesterol is the substrate for cholesterol 7alpha-hydroxylase. The specific activities of cholesteryl esters and 7alpha-hydroxycholeste  ol in incubations of microsomes labelled with (14C)cholesterol in vitro or in vivo suggest that 7alpha-hydroxycholesterol and esterified cholesterol are not derived from the same pool of free cholesterol.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002790:Cholesterol 7-alpha-Hydroxylase / Q000378:metabolism*; D003065:Coenzyme A / Q000494:pharmacology; D004952:Esters; D007700:Kinetics; D008862:Microsomes, Liver / Q000201:enzymology*; D009249:NADP / Q000494:pharmacology; D010084:Oxidation-Reduction; D051381:Rats; D013250:Steroid Hydroxylases / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013997:Time Factors
chemical_list: D004952:Esters; D009249:NADP; D000255:Adenosine Triphosphate; D013250:Steroid Hydroxylases; D002790:Cholesterol 7-alpha-Hydroxylase; D003065:Coenzyme A