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EC 1.14.99.38 Details

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EC number

1.14.99.38

Accepted name

cholesterol 25-monooxygenase

Reaction

cholesterol + reduced acceptor + O₂ = 25-hydroxycholesterol + acceptor + H₂O

Other name(s)

cholesterol 25-hydroxylase (ambiguous)

Systematic name

cholesterol,hydrogen-donor:oxygen oxidoreductase (25-hydroxylating)

CAS registry number

60202-07-5

Comment

Unlike most other sterol hydroxylases, this enzyme is not a cytochrome P-450. Instead, it uses diiron cofactors to catalyse the hydroxylation of hydrophobic substrates [1]. The diiron cofactor can be either Fe-O-Fe or Fe-OH-Fe and is bound to the enzyme through interactions with clustered histidine or glutamate residues [4,5]. In cell cultures, this enzyme down-regulates cholesterol synthesis and the processing of sterol regulatory element binding proteins (SREBPs). cf. EC 1.17.99.10, cholesterol C-25 hydroxylase.

History

created 2005, modified 2020

EC Tree

1 Oxidoreductases

1.1 Acting on the CH-OH group of donors

1.1.1 With NAD⁺ or NADP⁺ as acceptor

1.1.2 With a cytochrome as acceptor

1.1.3 With oxygen as acceptor

1.1.4 With a disulfide as acceptor

1.1.5 With a quinone or similar compound as acceptor

1.1.7 With an iron-sulfur protein as acceptor

1.1.9 With a copper protein as acceptor

1.1.98 With other, known, physiological acceptors

1.1.99 With unknown physiological acceptors

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

1.7 Acting on other nitrogenous compounds as donors

1.8 Acting on a sulfur group of donors

1.8.1 With NAD⁺ or NADP⁺ as acceptor

1.8.2 With a cytochrome as acceptor

1.8.3 With oxygen as acceptor

1.8.4 With a disulfide as acceptor

1.8.5 With a quinone or similar compound as acceptor

1.8.6 With a nitrogenous group as acceptor (deleted sub-subclass)

1.8.7 With an iron-sulfur protein as acceptor

1.8.98 With other, known, physiological acceptors

1.8.99 With unknown physiological acceptors

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

1.12 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

1.15 Acting on superoxide as acceptor

1.16 Oxidizing metal ions

1.17 Acting on CH or CH₂ groups

1.17.1 With NAD⁺ or NADP⁺ as acceptor

1.17.1.1 CDP-4-dehydro-6-deoxyglucose reductase

1.17.1.2 4-hydroxy-3-methylbut-2-enyl diphosphate reductase

1.17.1.3 leucoanthocyanidin reductase

1.17.1.4 xanthine dehydrogenase

1.17.1.5 nicotinate dehydrogenase

1.17.1.6 bile-acid 7α-dehydroxylase

1.17.1.7 3-oxo-5,6-dehydrosuberyl-CoA semialdehyde dehydrogenase

1.17.1.8 4-hydroxy-tetrahydrodipicolinate reductase

1.17.1.9 formate dehydrogenase

1.17.1.10 formate dehydrogenase (NADP⁺)

1.17.1.11 formate dehydrogenase (NAD⁺, ferredoxin)

1.17.2 With a cytochrome as acceptor

1.17.3 With oxygen as acceptor

1.17.4 With a disulfide as acceptor

1.17.5 With a quinone or similar compound as acceptor

1.17.7 With an iron-sulfur protein as acceptor

1.17.8 With a flavin as acceptor

1.17.9 With a copper protein as acceptor

1.17.98 With other, known, physiological acceptors

1.17.99 With unknown physiological acceptors

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

1.23 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)