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EC 1.14.18.8 Details

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EC number

1.14.18.8

Accepted name

7α-hydroxycholest-4-en-3-one 12α-hydroxylase

Reaction

7α-hydroxycholest-4-en-3-one + 2 ferrocytochrome b₅ + 2 H⁺ + O₂ = 7α,12α-dihydroxycholest-4-en-3-one + 2 ferricytochrome b₅ + + H₂O

Other name(s)

7α-hydroxy-4-cholesten-3-one 12α-monooxygenase, CYP12, sterol 12α-hydroxylase (ambiguous), HCO 12α-hydroxylase

Systematic name

7α-hydroxycholest-4-en-3-one,ferrocytochrome-b₅:oxygen oxidoreductase (12α-hydroxylating)

Comment

A P-450 heme-thiolate protein. Requires EC 1.6.2.4, NADPH—hemoprotein reductase and cytochrome b₅ for maximal activity. This enzyme is important in bile acid biosynthesis, being responsible for the balance between the formation of cholic acid and chenodeoxycholic acid [2].

History

created 2005 as EC 1.14.13.95, transferred 2015 to EC 1.14.18.8, deleted 2020

EC Tree

1 Oxidoreductases

1.1 Acting on the CH-OH group of donors

1.2 Acting on the aldehyde or oxo group of donors

1.3 Acting on the CH-CH group of donors

1.4 Acting on the CH-NH₂ group of donors

1.5 Acting on the CH-NH group of donors

1.6 Acting on NADH or NADPH

1.6.1 With NAD⁺ or NADP⁺ as acceptor

1.6.2 With a heme protein as acceptor

1.6.3 With oxygen as acceptor

1.6.4 With a disulfide as acceptor (deleted sub-subclass)

1.6.5 With a quinone or similar compound as acceptor

1.6.6 With a nitrogenous group as acceptor

1.6.7 With an iron-sulfur protein as acceptor (deleted sub-subclass)

1.6.8 With a flavin as acceptor (deleted sub-subclass)

1.6.99 With unknown physiological acceptors

1.7 Acting on other nitrogenous compounds as donors

1.8 Acting on a sulfur group of donors

1.9 Acting on a heme group of donors

1.10 Acting on diphenols and related substances as donors

1.11 Acting on a peroxide as acceptor

1.11.1 Peroxidases

1.11.2 Peroxygenases

1.12 Acting on hydrogen as donor

1.13 Acting on single donors with incorporation of molecular oxygen (oxygenases)

1.14 Acting on paired donors, with incorporation or reduction of molecular oxygen

1.14.1 With NADH or NADPH as one donor (deleted sub-subclass)

1.14.2 With ascorbate as one donor (deleted sub-subclass)

1.14.3 With reduced pteridine as one donor (deleted sub-subclass)

1.14.11 With 2-oxoglutarate as one donor, and incorporation of one atom of oxygen into each donor

1.14.12 With NADH or NADPH as one donor, and incorporation of two atoms of oxygen into the other donor

1.14.13 With NADH or NADPH as one donor, and incorporation of one atom of oxygen into the other donor

1.14.14 With reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen into the other donor

1.14.15 With reduced iron-sulfur protein as one donor, and incorporation of one atom of oxygen into the other donor

1.14.16 With reduced pteridine as one donor, and incorporation of one atom of oxygen into the other donor

1.14.17 With reduced ascorbate as one donor, and incorporation of one atom of oxygen into the other donor

1.14.18 With another compound as one donor, and incorporation of one atom of oxygen into the other donor

1.14.18.1 tyrosinase

1.14.18.2 CMP-N-acetylneuraminate monooxygenase

1.14.18.3 methane monooxygenase (particulate)

1.14.18.4 phosphatidylcholine 12-monooxygenase

1.14.18.5 sphingolipid C4-monooxygenase

1.14.18.6 4-hydroxysphinganine ceramide fatty acyl 2-hydroxylase

1.14.18.7 dihydroceramide fatty acyl 2-hydroxylase

1.14.18.8 7α-hydroxycholest-4-en-3-one 12α-hydroxylase

1.14.18.9 4α-methylsterol monooxygenase

1.14.18.10 plant 4,4-dimethylsterol C-4α-methyl-monooxygenase

1.14.18.11 plant 4α-monomethylsterol monooxygenase

1.14.18.12 2-hydroxy fatty acid dioxygenase

1.14.19 With oxidation of a pair of donors resulting in the reduction of O₂ to two molecules of water

1.14.20 With 2-oxoglutarate as one donor, and the other dehydrogenated

1.14.21 With NADH or NADPH as one donor, and the other dehydrogenated

1.14.99 Miscellaneous

1.15 Acting on superoxide as acceptor

1.16 Oxidizing metal ions

1.17 Acting on CH or CH₂ groups

1.18 Acting on iron-sulfur proteins as donors

1.19 Acting on reduced flavodoxin as donor

1.20 Acting on phosphorus or arsenic in donors

1.21 Catalysing the reaction X-H + Y-H = X-Y

1.21.1 With NAD⁺ or NADP⁺ as acceptor

1.21.3 With oxygen as acceptor

1.21.4 With a disulfide as acceptor

1.21.98 With other, known, physiological acceptors

1.21.99 With unknown physiological acceptors

1.22 Acting on halogen in donors

1.22.1 With NAD⁺ or NADP⁺ as acceptor

1.23 Reducing C-O-C group as acceptor

1.97 Other oxidoreductases

1.98 Enzymes using H₂ as reductant (deleted subclass)

1.99 Other enzymes using O₂ as oxidant (deleted subclass)

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Release 2023.1 (January 2023)