cholesterol 25-hydroxylase activity KEGG_REACTION:R07218 cholesterol 25-monooxygenase activity EC:1.14.99.38 cholesterol,hydrogen-donor:oxygen oxidoreductase (25-hydroxylating) activity molecular_function RHEA:46132 Catalysis of the reaction: AH2 + cholesterol + O2 = 25-hydroxycholesterol + A + H2O. RHEA:21104 GO:0001567 MetaCyc:1.14.99.38-RXN steroid hydroxylase activity oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen