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In enzymology, a 24-hydroxycholesterol 7alpha-hydroxylase (EC 1.14.13.99) is an enzyme that catalyzes the chemical reaction

(24R)-cholest-5-ene-3beta,24-diol + NADPH + H + O₂ ${\displaystyle \rightleftharpoons }$ (24R)-cholest-5-ene-3beta,7alpha,24-triol + NADP + H₂O

The 4 substrates of this enzyme are (24R)-cholest-5-ene-3beta,24-diol, NADPH, H, and O₂, whereas its 3 products are (24R)-cholest-5-ene-3beta,7alpha,24-triol, NADP, and H₂O.

This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O2 with NADH or NADPH as one donor, and incorporation of one atom o oxygen into the other donor. The systematic name of this enzyme class is (24R)-cholest-5-ene-3beta,24-diol,NADPH:oxygen oxidoreductase (7alpha-hydroxylating). Other names in common use include 24-hydroxycholesterol 7alpha-monooxygenase, CYP39A1, and CYP39A1 oxysterol 7alpha-hydroxylase.

See also

• Steroidogenic enzyme

References

1. Li-Hawkins J, Lund EG, Bronson AD, Russell DW (2000). "Expression cloning of an oxysterol 7alpha-hydroxylase selective for 24-hydroxycholesterol". J. Biol. Chem. 275 (22): 16543–9. doi:10.1074/jbc.M001810200. PMID 10748047.
2. Ikeda H, Ueda M, Ikeda M, Kobayashi H, Honda Y (2003). "Oxysterol 7alpha-hydroxylase (CYP39A1) in the ciliary nonpigmented epithelium of bovine eye". Lab. Invest. 83 (3): 349–55. doi:10.1097/01.lab.0000059933.35157.40. PMID 12649335.
3. Russell DW (2003). "The enzymes, regulation, and genetics of bile acid synthesis". Annu. Rev. Biochem. 72: 137–74. doi:10.1146/annurev.biochem.72.121801.161712. PMID 12543708.

External links

• 24-hydroxycholesterol+7alpha-hydroxylase at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

• Biology

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• EC 1.14.13
• NADPH-dependent enzymes
• Enzymes of unknown structure
• EC 1.14.13 stubs