Reaction: cholesterol + NADPH + H+ + O2 = (24S)-24-hydroxycholesterol + NADP+ + H2O
For diagram click here.
Glossary: cholesterol = cholest-5-en-3β-ol
Other name(s): cholesterol 24-monooxygenase; CYP46; CYP46A1; cholesterol 24S-hydroxylase; cytochrome P450 46A1
Systematic name: cholesterol,NADPH:oxygen oxidoreductase (24-hydroxylating)
Comments: A heme-thiolate protein (P-450). The enzyme can also produce 25-hydroxycholesterol. In addition, it can further hydroxylate the product to 24,25-dihydroxycholesterol and 24,27-dihydroxycholesterol . This reaction is the first step in the enzymatic degradation of cholesterol in the brain as hydroxycholesterol can pass the bloodbrain barrier whereas cholesterol cannot .
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 50812-30-1, 213327-78-7
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