Entry
Name
5beta-cholestane-3alpha,7alpha-diol 12alpha-hydroxylase;
5beta-cholestane-3alpha,7alpha-diol 12alpha-monooxygenase;
sterol 12alpha-hydroxylase (ambiguous);
CYP8B1;
cytochrome P450 8B1;
7alpha-hydroxycholest-4-en-3-one 12alpha-hydroxylase;
7alpha-hydroxy-4-cholesten-3-one 12alpha-monooxygenase;
chenodeoxycholate 12alpha monooxygenase
Class
Oxidoreductases;
Acting on paired donors, with incorporation or reduction of molecular oxygen;
With reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen into the other donor
BRITE hierarchy
Sysname
5beta-cholestane-3alpha,7alpha-diol,[reduced NADPH---hemoprotein reductase]:oxygen oxidoreductase (12alpha-hydroxylating)
Reaction(IUBMB)
(1) 5beta-cholestane-3alpha,7alpha-diol + [reduced NADPH---hemoprotein reductase] + O2 = 5beta-cholestane-3alpha,7alpha,12alpha-triol + [oxidized NADPH---hemoprotein reductase] + H2O [RN:
R07204 ];
(2) 7alpha-hydroxycholest-4-en-3-one + [reduced NADPH---hemoprotein reductase] + O2 = 7alpha,12alpha-dihydroxycholest-4-en-3-one + [oxidized NADPH---hemoprotein reductase] + H2O [RN:
R04826 ];
(3) chenodeoxycholate + [reduced NADPH---hemoprotein reductase] + O2 = cholate + [oxidized NADPH---hemoprotein reductase] + H2O [RN:
R12550 ]
Reaction(KEGG)
Substrate
5beta-cholestane-3alpha,7alpha-diol [CPD:
C05452 ];
[reduced NADPH---hemoprotein reductase] [CPD:
C03024 ];
O2 [CPD:
C00007 ];
7alpha-hydroxycholest-4-en-3-one [CPD:
C05455 ];
chenodeoxycholate [CPD:
C02528 ]
Product
5beta-cholestane-3alpha,7alpha,12alpha-triol [CPD:
C05454 ];
[oxidized NADPH---hemoprotein reductase] [CPD:
C03161 ];
H2O [CPD:
C00001 ];
7alpha,12alpha-dihydroxycholest-4-en-3-one;
cholate [CPD:
C00695 ]
Comment
A cytochrome P-450 (heme-thiolate) protein found in mammals. This is the key enzyme in the biosynthesis of the bile acid cholate. The enzyme can also hydroxylate 5beta-cholestane-3alpha,7alpha-diol at the 25 and 26 position, but to a lesser extent [2].
History
EC 1.14.14.139 created 2005 as EC 1.14.13.96, transferred 2018 to EC 1.14.14.139 (EC 1.14.18.8 created 2005 as EC 1.14.13.95, transferred 2015 to EC 1.14.18.8, incorporated 2020) , modified 2020
Pathway
ec00120 Primary bile acid biosynthesis
Orthology
K07431 sterol 12-alpha-hydroxylase
Genes
MMUR : 105874433 105874434
CPOC : 100734566 100734845
MDO : 100026525 100026549(CYP8B)
SHR : 100918099 100919664 100926550 105749568
ACS : 100551676 100551876 100562756 100562953 100565509 100565705 100565905 100566106
PVT : 110091568 110091574 110091575
SUND : 121932425 121934688 121935162 121935580 121935581
PMUR : 107284342 107284343 107284344 107284346 107284348 107284362
PGUT : 117680087 117680089
PMUA : 114607583 114607705 114607796 114607915
ZVI : 118091758 118091759 118091944
GJA : 107106985 107106986 107110695 107112093 107125164
STOW : 125440698 125441151
XLA : 108718630(cyp8b1.2.L) 379482(cyp8b1.1.S)
XTR : 100488015(cyp8b1.2) 100488168(cyp8b1.1)
BGAR : 122929107 122929108
DRE : 100004274(cyp8b2) 445281(cyp8b1) 447848(cyp8b3)
SANH : 107661909 107671665
SGH : 107558014 107580338 107593879
CCAR : 109056773 109056779 109056788
CAUA : 113038725 113038733 113046101
PPRM : 120477644 120479271
IPU : 108261592 108268189 108268197
PHYP : 113524124 113524125
TRU : 101070868 101071841 101080232 115248012 115248013
TNG : GSTEN00016125G001 GSTEN00016134G001
ELY : 117269563 117272242 117272243
PLEP : 121939385 121952022
PFLV : 114565114 114570013
MZE : 101474730 106675939 106676194
ONL : 100693750 109195682 109195683 109195699
OAU : 116316201 116316225 120434437
ALIM : 106533255 106533266
AOCE : 111568649 111568654
POV : 109625444 109637167 109638123
SSEN : 122767875 122767883 122767892 122767898 122767900 122768649 122768658 122779511
HHIP : 117777688 117777689
BPEC : 110154953 110159864
BSPL : 114843905 114845031 114845073
SASA : 106569335 106599887 106599889
OTW : 112226785 112226786 112260644
OGO : 124010151 124040889 124041735
ONE : 115102943 115102944 115114571
SNH : 120019994 120020264 120055983
ELS : 105019795 105019804 106024913
SFM : 108919335 108937621 114910968 114910986
LOC : 102682983 102694619 102694818
PSPA : 121311421 121311422 121312642 121312643 121312849 121314286 121314287 121314288 121314311 121314312
ARUT : 117394306 117394549 117394961 117399933
» show all
Taxonomy
Reference
Authors
Hansson R, Wikvall K.
Title
Hydroxylations in biosynthesis and metabolism of bile acids. Catalytic properties of different forms of cytochrome P-450.
Journal
J Biol Chem 255:1643-9 (1980)
Reference
Authors
Hansson R, Wikvall K.
Title
Hydroxylations in biosynthesis of bile acids. Cytochrome P-450 LM4 and 12alpha-hydroxylation of 5beta-cholestane-3alpha, 7alpha-diol.
Journal
Reference
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 267:21319-23 (1992)
Reference
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
Sequence
Reference
Authors
Lundell K, Wikvall K.
Title
Gene structure of pig sterol 12alpha-hydroxylase (CYP8B1) and expression in fetal liver: comparison with expression of taurochenodeoxycholic acid 6alpha-hydroxylase (CYP4A21).
Journal
Sequence
Reference
Authors
del Castillo-Olivares A, Gil G.
Title
Alpha 1-fetoprotein transcription factor is required for the expression of sterol 12alpha -hydroxylase, the specific enzyme for cholic acid synthesis. Potential role in the bile acid-mediated regulation of gene transcription.
Journal
Reference
Authors
Yang Y, Zhang M, Eggertsen G, Chiang JY.
Title
On the mechanism of bile acid inhibition of rat sterol 12alpha-hydroxylase gene (CYP8B1) transcription: roles of alpha-fetoprotein transcription factor and hepatocyte nuclear factor 4alpha.
Journal
Reference
Authors
Russell DW
Title
The enzymes, regulation, and genetics of bile acid synthesis.
Journal
Sequence
Reference
Authors
Fan L, Joseph JF, Durairaj P, Parr MK, Bureik M.
Title
Conversion of chenodeoxycholic acid to cholic acid by human CYP8B1.
Journal
Other DBs