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Proteins/UNIPROT:Q9UNU6

CYP8B1

Protein·UNIPROT:Q9UNU67-alpha-hydroxycholest-4-en-3-one 12-alpha-hydroxylase

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Sterol 12-alpha-hydroxylase involved in primary bile acid biosynthesis by catalyzing the 12alpha-hydroxylation of key intermediates including 7alpha-hydroxycholest-4-en-3-one, 3alpha,7alpha-dihydroxy-5beta-cholestan-26-oate and chenodeoxycholate along the classic pathway. May also hydroxylate 5beta-cholestane-3alpha,7alpha-diol (By similarity). Functions as a monooxygenase, inserting one atom of molecular oxygen into substrates while reducing the second to water, using electrons supplied by NADPH via cytochrome P450 reductase (CPR) (By similarity). Controls biliary balance of cholic acid and chenodeoxycholic acid, thereby regulating intestinal absorption of dietary lipids (By similarity)..

Function from UniProtKB (Q9UNU6), read 2026-09-23. CC BY 4.0.

Curated compounds routed: 0

What the reference databases state

Inferred

Inferred — not reported by a source. Evidence key

Statements

39 statements

39 statements · 8 reference databases · Subject: CYP8B1 · Sources: Bgee, gene ontology, Hetionet, Human-GEM, Reactome, Rhea, UniProt, WikiPathways

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CYP8B1 covaries with SYN2ProteinHetionet hetionet:covaries:1582-6854Inferred only
CYP8B1 is expressed in liverAnatomyBgee ENSG00000180432Inferred only
CYP8B1 is expressed in right lobe of liverAnatomyBgee ENSG00000180432Inferred only
7alpha-hydroxycholest-4-en-3-one is metabolised by CYP8B1CompoundHuman-GEM MAR01590Inferred only
7alpha-hydroxycholest-4-en-3-one is metabolised by CYP8B1CompoundRhea RHEA:46752Inferred only
7alpha-hydroxycholest-4-en-3-one is metabolised by CYP8B1CompoundHuman-GEM MAR01589Inferred only
chenodeoxycholate is metabolised by CYP8B1CompoundRhea RHEA:65700Inferred only
lithocholic acid is metabolised by CYP8B1CompoundHuman-GEM MAR01839Inferred only
lithocholic acid is metabolised by CYP8B1CompoundHuman-GEM MAR01840Inferred only
CYP8B1 participates in Arachidonate metabolismPathwayReactome R-HSA-2142753Inferred only
CYP8B1 participates in Bile acid and bile salt metabolismPathwayReactome R-HSA-194068Inferred only
CYP8B1 participates in Biological oxidationsPathwayReactome R-HSA-211859Inferred only

Show the remaining 27

CYP8B1 participates in Cytochrome P450 - arranged by substrate typePathwayReactome R-HSA-211897Inferred only
CYP8B1 participates in Disorders of bile acid synthesis and biliary transportPathwayWikiPathways WP5176Inferred only
CYP8B1 participates in EicosanoidsPathwayReactome R-HSA-211979Inferred only
CYP8B1 participates in Endogenous sterolsPathwayReactome R-HSA-211976Inferred only
CYP8B1 participates in Farnesoid X receptor pathwayPathwayWikiPathways WP2879Inferred only
CYP8B1 participates in Fatty acid metabolismPathwayReactome R-HSA-8978868Inferred only
CYP8B1 participates in MetabolismPathwayReactome R-HSA-1430728Inferred only
CYP8B1 participates in Metabolism of lipidsPathwayReactome R-HSA-556833Inferred only
CYP8B1 participates in Metabolism of steroidsPathwayReactome R-HSA-8957322Inferred only
CYP8B1 participates in Metapathway biotransformation Phase I and IIPathwayWikiPathways WP702Inferred only
CYP8B1 participates in Nuclear receptors in lipid metabolism and toxicityPathwayWikiPathways WP299Inferred only
CYP8B1 participates in Nuclear receptors meta pathwayPathwayWikiPathways WP2882Inferred only
CYP8B1 participates in Oxidation by cytochrome P450PathwayWikiPathways WP43Inferred only
CYP8B1 participates in Oxysterols derived from cholesterolPathwayWikiPathways WP4545Inferred only
CYP8B1 participates in Phase I - Functionalization of compoundsPathwayReactome R-HSA-211945Inferred only
CYP8B1 participates in PPAR alpha pathwayPathwayWikiPathways WP2878Inferred only
CYP8B1 participates in PPAR signalingPathwayWikiPathways WP3942Inferred only
CYP8B1 participates in Signaling lipidsPathwayWikiPathways WP5584Inferred only
CYP8B1 participates in Sterols are 12-hydroxylated by CYP8B1PathwayReactome R-HSA-211994Inferred only
CYP8B1 participates in Synthesis of bile acids and bile saltsPathwayReactome R-HSA-192105Inferred only
CYP8B1 participates in Synthesis of bile acids and bile salts via 27-hydroxycholesterolPathwayReactome R-HSA-193807Inferred only
CYP8B1 participates in Synthesis of bile acids and bile salts via 7alpha-hydroxycholesterolPathwayReactome R-HSA-193368Inferred only
CYP8B1 participates in Synthesis of Prostaglandins (PG) and Thromboxanes (TX)PathwayReactome R-HSA-2162123Inferred only
CYP8B1 regulates positive regulation of intestinal cholesterol absorptionBiological processgene ontology Q9UNU6|GO:0045797Inferred only
CYP8B1 requires the cofactor hemeCompoundUniProt Q9UNU6Inferred only
(25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oyl-CoA is transported by CYP8B1CompoundHuman-GEM MAR01629Inferred only
(25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oyl-CoA is transported by CYP8B1CompoundHuman-GEM MAR01631Inferred only

Reactions

12 reactions

7alpha-hydroxycholest-4-en-3-one+proton+NADPH(4-)+dioxygenMAM01178r+water+NADP(3-)
Catalysed by CYP8B1
Reaction pageLeft to rightBalancedEC 1.14.14.139endoplasmic reticulum
Human-GEM MAR01589CC BY 4.0Reference data
7alpha-hydroxycholest-4-en-3-one+proton+NADH(2-)+dioxygen

Other names

5 names

Resolves to: CYP8B1

Also called: 7-alpha-hydroxy-4-cholesten-3-one 12-alpha-hydroxylaseCYP12CYPVIIIB1Cytochrome P450 8B1Sterol 12-alpha-hydroxylase

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MAM01178r

Catalysed by CYP8B1

Reaction pageLeft to rightBalancedEC 1.14.14.139endoplasmic reticulum

Human-GEM MAR01590CC BY 4.0Reference data

(25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oyl-CoA(25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oyl-CoA

Transported by CYP8B1

Reaction pageReversibleBalancedEC 1.14.14.139cytosol, peroxisome

Human-GEM MAR01629CC BY 4.0Reference data

(25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oyl-CoA(25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oyl-CoA

Transported by CYP8B1

Reaction pageReversibleBalancedEC 1.14.14.139cytosol, endoplasmic reticulum

Human-GEM MAR01631CC BY 4.0Reference data

MAM00978c+proton+NADPH(4-)+dioxygenMAM00976c+water+NADP(3-)

Catalysed by CYP8B1

Reaction pageLeft to rightBalancedEC 1.14.14.139cytosol

Human-GEM MAR01739CC BY 4.0Reference data

MAM00979c+proton+NADPH(4-)+dioxygenMAM00977c+water+NADP(3-)

Catalysed by CYP8B1

Reaction pageLeft to rightBalancedEC 1.14.14.139cytosol

Human-GEM MAR01767CC BY 4.0Reference data

proton+lithocholic acid+NADPH(4-)+dioxygendeoxycholate+water+NADP(3-)

Catalysed by CYP8B1

Reaction pageLeft to rightBalancedEC 1.14.14.139cytosol

Human-GEM MAR01839CC BY 4.0Reference data

proton+lithocholic acid+NADPH(4-)+dioxygendeoxycholate+water+NADP(3-)

Catalysed by CYP8B1

Reaction pageLeft to rightBalancedEC 1.14.14.139endoplasmic reticulum

Human-GEM MAR01840CC BY 4.0Reference data

CHEBI:28047+reduced [NADPH--hemoprotein reductase]+dioxygenCHEBI:16496+oxidized [NADPH--hemoprotein reductase]+water+hydron

Catalysed by CYP8B1

Reaction pageLeft to rightBalance undeterminable

Rhea RHEA:15261CC BY 4.0Reference data

7alpha-hydroxycholest-4-en-3-one+reduced [NADPH--hemoprotein reductase]+dioxygenCHEBI:28477+oxidized [NADPH--hemoprotein reductase]+water+hydron

Catalysed by CYP8B1

Reaction pageLeft to rightBalance undeterminable

Rhea RHEA:46752CC BY 4.0Reference data

chenodeoxycholate+reduced [NADPH--hemoprotein reductase]+dioxygencholate+oxidized [NADPH--hemoprotein reductase]+water+hydron

Catalysed by CYP8B1

Reaction pageLeft to rightBalance undeterminable

Rhea RHEA:65700CC BY 4.0Reference data

CHEBI:58750+reduced [NADPH--hemoprotein reductase]+dioxygen(25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oate+oxidized [NADPH--hemoprotein reductase]+water+hydron

Catalysed by CYP8B1

Reaction pageLeft to rightBalance undeterminable

Rhea RHEA:82331CC BY 4.0Reference data