CYP8B1

CYP8B1
Identifiers
Aliases	CYP8B1, CP8B, CYP12, cytochrome P450 family 8 subfamily B member 1
External IDs	OMIM: 602172; MGI: 1338044; HomoloGene: 3233; GeneCards: CYP8B1; OMA:CYP8B1 - orthologs
Gene location (Human)
Chr.	Chromosome 3 (human)
End	42,875,898 bp
Gene location (Mouse)
Chr.	Chromosome 9 (mouse)
End	121,745,371 bp
RNA expression pattern
	Top expressed in
	right lobe of liver; ; tibialis anterior muscle; ; sural nerve; ; pancreatic ductal cell; ; renal cortex; ; renal medulla; ; gallbladder; ; right coronary artery; ; left coronary artery; ; human kidney;
	Top expressed in
	left lobe of liver; ; gallbladder; ; sexually immature organism; ; medial head of gastrocnemius muscle; ; esophagus; ; lip; ; muscle of thigh; ; central gray substance of midbrain; ; nucleus of stria terminalis; ; pancreas;
	More reference expression data
	n/a
Gene ontology
Molecular function	monooxygenase activity; iron ion binding; oxygen binding; oxidoreductase activity; heme binding; oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen; metal ion binding; 7alpha-hydroxycholest-4-en-3-one 12alpha-hydroxylase activity; sterol 12-alpha-hydroxylase activity;
Cellular component	integral component of membrane; organelle membrane; endoplasmic reticulum membrane; endoplasmic reticulum; membrane; intracellular membrane-bounded organelle;
Biological process	sterol metabolic process; bile acid biosynthetic process;
	Sources:Amigo / QuickGO
Orthologs
	1582
	13124
	ENSG00000180432
	ENSMUSG00000050445
	Q9UNU6
	O88962
	NM_004391
	NM_010012
	NP_004382
	NP_034142
	Wikidata
View/Edit Human	View/Edit Mouse

CYP8B1 (cytochrome P450, family 8, subfamily B, polypeptide 1) also known as sterol 12-alpha-hydroxylase is a protein which in humans is encoded by the CYP8B1 gene.^[5]

This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids.

CYP8B1 is an endoplasmic reticulum membrane protein and catalyzes the conversion of 7 alpha-hydroxy-4-cholesten-3-one into 7-alpha,12-alpha-dihydroxy-4-cholesten-3-one. The balance between these two steroids determines the relative amounts of the two primary bile acids, cholic acid and chenodeoxycholic acid, both of which are secreted in the bile. In the intestine these bile acids affect the solubility of cholesterol and other lipids, promoting their absorption.

CYP8B1 is unique among the cytochrome P450 genes in that it is intronless.^[6]

The elephant, manatee and naked mole rat have inactive copies of this gene and lack cholic acid in their bile.^[7] Relaxed selection resulting from changes in diet to consume less lipids might have contributed to the loss of this gene in several species.^[8]

^ ^a ^b ^c GRCh38: Ensembl release 89: ENSG00000180432 – Ensembl, May 2017
^ ^a ^b ^c GRCm38: Ensembl release 89: ENSMUSG00000050445 – Ensembl, May 2017
^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^ Gåfvels M, Olin M, Chowdhary BP, Raudsepp T, Andersson U, Persson B, Jansson M, Björkhem I, Eggertsen G (March 1999). "Structure and chromosomal assignment of the sterol 12alpha-hydroxylase gene (CYP8B1) in human and mouse: eukaryotic cytochrome P-450 gene devoid of introns". Genomics. 56 (2): 184–96. doi:10.1006/geno.1998.5606. PMID 10051404.
^ This article incorporates public domain material from "Entrez Gene: CYP8B1". Reference Sequence collection. National Center for Biotechnology Information.
^ Sharma, V; Hiller, M (1 December 2018). "Loss of Enzymes in the Bile Acid Synthesis Pathway Explains Differences in Bile Composition among Mammals". Genome Biology and Evolution. 10 (12): 3211–3217. doi:10.1093/gbe/evy243. PMC 6296402. PMID 30388264.
^ Shinde, SS; Teekas, L; Sharma, S; Vijay, N (September 2019). "Signatures of Relaxed Selection in the CYP8B1 Gene of Birds and Mammals". Journal of Molecular Evolution. 87 (7–8): 209–220. Bibcode:2019JMolE..87..209S. doi:10.1007/s00239-019-09903-6. PMID 31372666. S2CID 199380339.

[refGRCh38Ensembl-1] GRCh38: Ensembl release 89: ENSG00000180432 – Ensembl, May 2017

[refGRCm38Ensembl-2] GRCm38: Ensembl release 89: ENSMUSG00000050445 – Ensembl, May 2017

[3] "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.

[4] "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.

[pmid10051404-5] Gåfvels M, Olin M, Chowdhary BP, Raudsepp T, Andersson U, Persson B, Jansson M, Björkhem I, Eggertsen G (March 1999). "Structure and chromosomal assignment of the sterol 12alpha-hydroxylase gene (CYP8B1) in human and mouse: eukaryotic cytochrome P-450 gene devoid of introns". Genomics. 56 (2): 184–96. doi:10.1006/geno.1998.5606. PMID 10051404.

[entrez-6] This article incorporates public domain material from "Entrez Gene: CYP8B1". Reference Sequence collection. National Center for Biotechnology Information.

[7] Sharma, V; Hiller, M (1 December 2018). "Loss of Enzymes in the Bile Acid Synthesis Pathway Explains Differences in Bile Composition among Mammals". Genome Biology and Evolution. 10 (12): 3211–3217. doi:10.1093/gbe/evy243. PMC 6296402. PMID 30388264.

[8] Shinde, SS; Teekas, L; Sharma, S; Vijay, N (September 2019). "Signatures of Relaxed Selection in the CYP8B1 Gene of Birds and Mammals". Journal of Molecular Evolution. 87 (7–8): 209–220. Bibcode:2019JMolE..87..209S. doi:10.1007/s00239-019-09903-6. PMID 31372666. S2CID 199380339.

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