Entry |
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Name |
cholestanetriol 26-monooxygenase;
5beta-cholestane-3alpha,7alpha,12alpha-triol 26-hydroxylase;
5beta-cholestane-3alpha,7alpha,12alpha-triol hydroxylase;
cholestanetriol 26-hydroxylase;
sterol 27-hydroxylase;
sterol 26-hydroxylase;
cholesterol 27-hydroxylase;
CYP27A;
CYP27A1;
cytochrome P450 27A1'
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Class |
Oxidoreductases;
Acting on paired donors, with incorporation or reduction of molecular oxygen;
With reduced iron-sulfur protein as one donor, and incorporation of one atom of oxygen into the other donor
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Sysname |
5beta-cholestane-3alpha,7alpha,12alpha-triol,adrenodoxin:oxygen oxidoreductase (26-hydroxylating)
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Reaction(IUBMB) |
5beta-cholestane-3alpha,7alpha,12alpha-triol + 6 reduced adrenodoxin + 6 H+ + 3 O2 = (25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oate + 6 oxidized adrenodoxin + 4 H2O (overall reaction) [RN: R11142];
(1a) 5beta-cholestane-3alpha,7alpha,12alpha-triol + 2 reduced adrenodoxin + 2 H+ + O2 = (25R)-5beta-cholestane-3alpha,7alpha,12alpha,26-tetraol + 2 oxidized adrenodoxin + H2O [RN: R04807];
(1b) (25R)-5beta-cholestane-3alpha,7alpha,12alpha,26-tetraol + 2 reduced adrenodoxin + 2 H+ + O2 = (25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-al + 2 oxidized adrenodoxin + 2 H2O [RN: R03507];
(1c) (25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-al + 2 reduced adrenodoxin + 2 H+ + O2 = (25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oate + 2 oxidized adrenodoxin + H2O [RN: R08761]
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Reaction(KEGG) |
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Substrate |
5beta-cholestane-3alpha,7alpha,12alpha-triol [CPD: C05454];
reduced adrenodoxin [CPD: C00662];
H+ [CPD: C00080];
O2 [CPD: C00007];
(25R)-5beta-cholestane-3alpha,7alpha,12alpha,26-tetraol;
(25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-al
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Product |
(25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oate;
oxidized adrenodoxin [CPD: C00667];
H2O [CPD: C00001];
(25R)-5beta-cholestane-3alpha,7alpha,12alpha,26-tetraol;
(25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-al
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Comment |
This mitochondrial cytochrome P-450 enzyme requires adrenodoxin. It catalyses the first three sterol side chain oxidations in bile acid biosynthesis via the neutral (classic) pathway. Can also act on cholesterol, cholest-5-ene-3beta,7alpha-diol, 7alpha-hydroxycholest-4-en-3-one, and 5beta-cholestane-3alpha,7alpha-diol. The enzyme can also hydroxylate cholesterol at positions 24 and 25. The initial source of the electrons is NADPH, which transfers the electrons to the adrenodoxin via EC 1.18.1.6, adrenodoxin-NADP+ reductase.
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History |
EC 1.14.15.15 created 1976 as EC 1.14.13.15, modified 2005, modified 2012, transferred 2016 to EC 1.14.15.15
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Pathway |
ec00120 | Primary bile acid biosynthesis |
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Orthology |
K00488 | cholestanetriol 26-monooxygenase |
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Genes |
» show all
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Reference |
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Authors |
Masui T, Herman R, Staple E. |
Title |
The oxidation of 5-beta-cholestane-3-alpha, 7-alpha, 12-alpha, 26-tetraol to 5-beta-cholestane-3-alpha, 7-alpha, 12-alpha-triol-26-oic acid via 5-beta-cholestane-3-alpha, 7-alpha, 12-alpha-triol-26-al by rat liver. |
Journal |
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Reference |
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Authors |
Okuda K, Hoshita N. |
Title |
Oxidation of 5-beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol by rat-liver mitochondria. |
Journal |
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Reference |
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Authors |
Wikvall K. |
Title |
Hydroxylations in biosynthesis of bile acids. Isolation of a cytochrome P-450 from rabbit liver mitochondria catalyzing 26-hydroxylation of C27-steroids. |
Journal |
J Biol Chem 259:3800-4 (1984) |
Reference |
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Authors |
Andersson S, Davis DL, Dahlback H, Jornvall H, Russell DW |
Title |
Cloning, structure, and expression of the mitochondrial cytochrome P-450 sterol 26-hydroxylase, a bile acid biosynthetic enzyme. |
Journal |
J Biol Chem 264:8222-9 (1989) |
Sequence |
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Reference |
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Authors |
Dahlback H, Holmberg I |
Title |
Oxidation of 5 beta-cholestane-3 alpha,7 alpha, 12 alpha-triol into 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid by cytochrome P-450(26) from rabbit liver mitochondria. |
Journal |
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Reference |
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Authors |
Holmberg-Betsholtz I, Lund E, Bjorkhem I, Wikvall K. |
Title |
Sterol 27-hydroxylase in bile acid biosynthesis. Mechanism of oxidation of 5 beta-cholestane-3 alpha,7 alpha,12 alpha,27-tetrol into 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid. |
Journal |
J Biol Chem 268:11079-85 (1993) |
Reference |
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Authors |
Pikuleva IA, Babiker A, Waterman MR, Bjorkhem I |
Title |
Activities of recombinant human cytochrome P450c27 (CYP27) which produce intermediates of alternative bile acid biosynthetic pathways. |
Journal |
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Reference |
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Authors |
Furster C, Bergman T, Wikvall K. |
Title |
Biochemical characterization of a truncated form of CYP27A purified from rabbit liver mitochondria. |
Journal |
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Reference |
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Authors |
Pikuleva IA, Puchkaev A, Bjorkhem I |
Title |
Putative helix F contributes to regioselectivity of hydroxylation in mitochondrial cytochrome P450 27A1. |
Journal |
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Sequence |
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Other DBs |
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LinkDB |
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