KEGG   ENZYME: 1.14.13.95Help
Entry
EC 1.14.13.95               Enzyme                                 
Name
7alpha-hydroxycholest-4-en-3-one 12alpha-hydroxylase;
7alpha-hydroxy-4-cholesten-3-one 12alpha-monooxygenase;
CYP12;
sterol 12alpha-hydroxylase (ambiguous);
HCO 12alpha-hydroxylase
Class
Oxidoreductases;
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 of oxygen into the other donor
BRITE hierarchy
Sysname
7alpha-hydroxycholest-4-en-3-one,NADPH:oxygen oxidoreductase (12alpha-hydroxylating)
Reaction(IUBMB)
7alpha-hydroxycholest-4-en-3-one + NADPH + H+ + O2 = 7alpha,12alpha-dihydroxycholest-4-en-3-one + NADP+ + H2O [RN:R04826]
Reaction(KEGG)
Substrate
7alpha-hydroxycholest-4-en-3-one [CPD:C05455];
NADPH [CPD:C00005];
H+ [CPD:C00080];
O2 [CPD:C00007]
Product
7alpha,12alpha-dihydroxycholest-4-en-3-one;
NADP+ [CPD:C00006];
H2O [CPD:C00001]
Comment
A heme-thiolate protein (P-450). 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].
Pathway
Metabolic pathways
Orthology
K07431  
cytochrome P450, family 8, subfamily B (sterol 12-alpha-hydroxylase)
Genes
HSA: 
1582(CYP8B1)
PTR: 
PPS: 
GGO: 
PON: 
MCC: 
MMU: 
13124(Cyp8b1)
RNO: 
81924(Cyp8b1)
CFA: 
AML: 
FCA: 
101082004
BTA: 
538964(CYP8B1)
SSC: 
403328(CYP8B1)
ECB: 
100054970
MDO: 
100026549(CYP8B)
SHR: 
100926813
OAA: 
100082225
GGA: 
425055(CYP8B1)
MGP: 
100546803
TGU: 
100217899
ACS: 
100551876
XLA: 
379482(cyp8b1)
XTR: 
100488168
DRE: 
445281
TRU: 
101071841 101080232
OLA: 
101157008
UMA: 
UM04362.1
 » show all
Taxonomy
Reference
1  [PMID:1400444]
  Authors
Ishida H, Noshiro M, Okuda K, Coon MJ.
  Title
Purification and characterization of 7 alpha-hydroxy-4-cholesten-3-one 12 alpha-hydroxylase.
  Journal
J. Biol. Chem. 267 (1992) 21319-23.
  Organism
Oryctolagus cuniculus
Reference
2  [PMID:8943286]
  Authors
Eggertsen G, Olin M, Andersson U, Ishida H, Kubota S, Hellman U, Okuda KI, Bjorkhem I.
  Title
Molecular cloning and expression of rabbit sterol 12alpha-hydroxylase.
  Journal
J. Biol. Chem. 271 (1996) 32269-75.
  Organism
Oryctolagus cuniculus
Reference
3  [PMID:12543708]
  Authors
Russell DW.
  Title
The enzymes, regulation, and genetics of bile acid synthesis.
  Journal
Annu. Rev. Biochem. 72 (2003) 137-74.
Other DBs
ExplorEnz - The Enzyme Database: 
IUBMB Enzyme Nomenclature: 
ExPASy - ENZYME nomenclature database: 
BRENDA, the Enzyme Database: 
DBGET integrated database retrieval system