KEGG   ENZYME: 1.14.13.15Help
Entry
EC 1.14.13.15               Enzyme                                 

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'
Class
Oxidoreductases;
Acting on paired donors, with incorporation or reduction of molecular oxygen;
With NADH or NADPH as one donor, and incorporation of one atom of oxygen into the other donor
BRITE hierarchy
Sysname
5beta-cholestane-3alpha,7alpha,12alpha-triol,NADPH:oxygen oxidoreductase (26-hydroxylating)
Reaction(IUBMB)
5beta-cholestane-3alpha,7alpha,12alpha-triol + 3 NADPH + 3 H+ + 3 O2 = (25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oate + 3 NADP+ + 4 H2O (overall reaction) [RN:R04807];
(1a) 5beta-cholestane-3alpha,7alpha,12alpha-triol + NADPH + H+ + O2 = (25R)-5beta-cholestane-3alpha,7alpha,12alpha,26-tetraol + NADP+ + H2O;
(1b) (25R)-5beta-cholestane-3alpha,7alpha,12alpha,26-tetraol + NADPH + H+ + O2 = (25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-al + NADP+ + 2 H2O;
(1c) (25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-al + NADPH + H+ + O2 = (25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oate + NADP+ + H2O
Reaction(KEGG)
Substrate
5beta-cholestane-3alpha,7alpha,12alpha-triol [CPD:C05454];
NADPH [CPD:C00005];
H+ [CPD:C00080];
O2 [CPD:C00007];
(25R)-5beta-cholestane-3alpha,7alpha,12alpha,26-tetraol;
(25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-al
Product
(25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oate;
NADP+ [CPD:C00006];
H2O [CPD:C00001];
(25R)-5beta-cholestane-3alpha,7alpha,12alpha,26-tetraol;
(25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-al
Comment
The enzyme requires ferredoxin and ferredoxin reductase. 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-en-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.
History
EC 1.14.13.15 created 1976, modified 2005, modified 2012
Pathway
Primary bile acid biosynthesis
Metabolic pathways
Orthology
K00488  
cholestanetriol 26-monooxygenase
Genes
HSA: 
1593(CYP27A1)
PTR: 
PPS: 
GGO: 
PON: 
MCC: 
700192(CYP27A1)
MCF: 
MMU: 
104086(Cyp27a1)
RNO: 
301517(Cyp27a1)
CGE: 
HGL: 
TUP: 
CFA: 
610489(CYP27A1)
AML: 
FCA: 
PTG: 
BTA: 
511960(CYP27A1)
BOM: 
PHD: 
CHX: 
SSC: 
100126282(CYP27A1)
CFR: 
BACU: 
LVE: 
ECB: 
MYB: 
MYD: 
PALE: 
MDO: 
100011045(CYP27A1)
SHR: 
OAA: 
GGA: 
431683(CYP27A1)
MGP: 
TGU: 
FAB: 
PHI: 
APLA: 
FPG: 
FCH: 
CLV: 
ASN: 
AMJ: 
CMY: 
ACS: 
PBI: 
XLA: 
446987(cyp27a1)
XTR: 
DRE: 
322341(cyp27a1.4) 565876 795106(cyp27a1.2)
TRU: 
MZE: 
OLA: 
XMA: 
LCM: 
CMK: 
BFO: 
AQU: 
EHX: 
NGR: 
 » show all
Taxonomy
Reference
1  [PMID:5914340]
  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
Biochim. Biophys. Acta. 117 (1966) 266-8.
Reference
2  [PMID:4388637]
  Authors
Okuda K, Hoshita N.
  Title
Oxidation of 5-beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol by rat-liver mitochondria.
  Journal
Biochim. Biophys. Acta. 164 (1968) 381-8.
  Organism
Rattus norvegicus
Reference
3  [PMID:6423637]
  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 (1984) 3800-4.
  Organism
Oryctolagus cuniculus
Reference
4  [PMID:2722778]
  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 (1989) 8222-9.
  Organism
Oryctolagus cuniculus
  Sequence
[up:P17177]
Reference
5  [PMID:2322231]
  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
Biochem. Biophys. Res. Commun. 167 (1990) 391-5.
Reference
6  [PMID:8496170]
  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 (1993) 11079-85.
  Organism
Oryctolagus cuniculus
Reference
7  [PMID:9660774]
  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
J. Biol. Chem. 273 (1998) 18153-60.
Reference
8  [PMID:10512735]
  Authors
Furster C, Bergman T, Wikvall K.
  Title
Biochemical characterization of a truncated form of CYP27A purified from rabbit liver mitochondria.
  Journal
Biochem. Biophys. Res. Commun. 263 (1999) 663-6.
  Organism
Oryctolagus cuniculus
Reference
9  [PMID:11412116]
  Authors
Pikuleva IA, Puchkaev A, Bjorkhem I.
  Title
Putative helix F contributes to regioselectivity of hydroxylation in mitochondrial cytochrome P450 27A1.
  Journal
Biochemistry. 40 (2001) 7621-9.
  Organism
Homo sapiens
  Sequence
[hsa:1593]
Other DBs
ExplorEnz - The Enzyme Database: 
IUBMB Enzyme Nomenclature: 
ExPASy - ENZYME nomenclature database: 
BRENDA, the Enzyme Database: 
CAS: 
52227-77-7

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