KEGG   ENZYME: 1.14.13.100Help
Entry
EC 1.14.13.100              Enzyme                                 
Name
25-hydroxycholesterol 7alpha-hydroxylase;
25-hydroxycholesterol 7alpha-monooxygenase;
CYP7B1;
CYP7B1 oxysterol 7alpha-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
cholest-5-ene-3beta,25-diol,NADPH:oxygen oxidoreductase (7alpha-hydroxylating)
Reaction(IUBMB)
(1) cholest-5-ene-3beta,25-diol + NADPH + H+ + O2 = cholest-5-ene-3beta,7alpha,25-triol + NADP+ + H2O [RN:R07209];
(2) cholest-5-ene-3beta,27-diol + NADPH + H+ + O2 = cholest-5-ene-3beta,7alpha,27-triol + NADP+ + H2O [RN:R07372]
Reaction(KEGG)
Substrate
cholest-5-ene-3beta,25-diol [CPD:C15519];
NADPH [CPD:C00005];
H+ [CPD:C00080];
O2 [CPD:C00007];
cholest-5-ene-3beta,27-diol [CPD:C15610]
Product
cholest-5-ene-3beta,7alpha,25-triol [CPD:C15520];
NADP+ [CPD:C00006];
H2O [CPD:C00001];
cholest-5-ene-3beta,7alpha,27-triol [CPD:C06341]
Comment
A heme-thiolate protein (P-450). Unlike EC 1.14.13.99, 24-hydroxycholesterol 7alpha-monooxygenase, which is specific for its oxysterol substrate, this enzyme can also metabolize the oxysterols 24,25-epoxycholesterol, 22-hydroxycholesterol and 24-hydroxycholesterol, but to a lesser extent [2].
Pathway
Primary bile acid biosynthesis
Steroid hormone biosynthesis
Orthology
K07430  
cytochrome P450, family 7, subfamily B (oxysterol 7-alpha-hydroxylase)
Genes
HSA: 
9420(CYP7B1)
PTR: 
PPS: 
GGO: 
PON: 
MCC: 
MMU: 
13123(Cyp7b1)
RNO: 
25429(Cyp7b1)
CFA: 
486973(CYP7B1)
AML: 
FCA: 
101086873
BTA: 
529552(CYP7B1)
SSC: 
100286867(CYP7B1)
ECB: 
100064741
MDO: 
100029487(CYP7B1)
SHR: 
100920521
OAA: 
100081634
GGA: 
420164(CYP7B1)
MGP: 
100541042
TGU: 
100224987
ACS: 
100564185
XTR: 
100145642(cyp7b1)
DRE: 
570455
OLA: 
101173499
CIN: 
100184784
 » show all
Taxonomy
Reference
1  [PMID:7925343]
  Authors
Toll A, Wikvall K, Sudjana-Sugiaman E, Kondo KH, Bjorkhem I.
  Title
7 alpha hydroxylation of 25-hydroxycholesterol in liver microsomes. Evidence that the enzyme involved is different from cholesterol 7 alpha-hydroxylase.
  Journal
Eur. J. Biochem. 224 (1994) 309-16.
  Organism
Homo sapiens [GN:hsa], Rattus norvegicus [GN:rno], Sus scofa [GN:ssc]
Reference
2  [PMID:10748047]
  Authors
Li-Hawkins J, Lund EG, Bronson AD, Russell DW.
  Title
Expression cloning of an oxysterol 7alpha-hydroxylase selective for 24-hydroxycholesterol.
  Journal
J. Biol. Chem. 275 (2000) 16543-9.
  Organism
Homo sapiens [GN:hsa], Mus musculus [GN:mmu]
Reference
3  [PMID:12759897]
  Authors
Ren S, Marques D, Redford K, Hylemon PB, Gil G, Vlahcevic ZR, Pandak WM.
  Title
Regulation of oxysterol 7alpha-hydroxylase (CYP7B1) in the rat.
  Journal
Metabolism. 52 (2003) 636-42.
  Organism
Rattus norvegicus [GN:rno]
Reference
4  [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