Chymotrypsinogen B1

CTRB1
Identifiers
Aliases	CTRB1, CTRB, chymotrypsinogen B1
External IDs	OMIM: 118890; MGI: 88559; GeneCards: CTRB1
Enzyme activity
Gene location (Human)
Chr.	Chromosome 16 (human)
End	75,226,338 bp
Gene location (Mouse)
Chr.	Chromosome 8 (mouse)
End	112,417,642 bp
RNA expression pattern
	Top expressed in
	body of pancreas; ; islet of Langerhans; ; duodenum; ; fundus; ; right coronary artery; ; ectocervix; ; right uterine tube; ; canal of the cervix; ; testicle; ; right adrenal gland;
	Top expressed in
	pyloric antrum; ; islet of Langerhans; ; migratory enteric neural crest cell; ; cardiac muscle tissue of left ventricle; ; plantaris muscle; ; extensor digitorum longus muscle; ; interventricular septum; ; duodenum; ; corneal stroma; ; sexually immature organism;
	More reference expression data
	n/a
Gene ontology
Molecular function	peptidase activity; hydrolase activity; serine-type peptidase activity; serine-type endopeptidase activity;
Cellular component	extracellular region; extracellular space;
Biological process	digestion; cobalamin metabolic process; extracellular matrix disassembly; proteolysis;
	Sources:Amigo / QuickGO
Orthologs
Databases	NCBI: entry; OMA: entry
	1504
	66473
	ENSG00000168925; ENSG00000285346
	ENSMUSG00000031957
	P17538
	Q9CR35
	NM_001906; NM_001329190
	NM_025583
	NP_001316119; NP_001897
	NP_079859
	Wikidata
View/Edit Human	View/Edit Mouse

Chymotrypsinogen B1 (or sometimes just Chymotrypsinogen B) is a protein that in humans is encoded by the CTRB1 gene. Similar to its paralog chymotrypsinogen B2, chymotrypsiongen B1 is an inactive precursor for an enzyme which is an isozyme of chymotrypsin. It is secreted by the acinar cells of the pancreas into the small intestines as part of pancreatic juice, where it is activated. After activation it functions as a protease which is involved in breaking down other proteins as part of digestion.

Medical significance

The CTRB1 and CTRB2 genes are located near each other on chromosome 16. In some populations there is an inversion which causes certain parts of each gene to be swapped, which has been associated with an increased risk of chronic pancreatitis.

References

1 2 3 ENSG00000285346 GRCh38: Ensembl release 89: ENSG00000168925, ENSG00000285346 – Ensembl, May 2017
1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000031957 – 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.
1 2 3 4 5 "Entrez Gene: Chymotrypsinogen B1". Retrieved 2026-09-01.
↑ "P17538 · CTRB1_HUMAN". uniprot.org. UniProt consortium. Retrieved 2026-09-01.
↑ Pandol SJ (2010). "Anatomy". The Exocrine Pancreas. Morgan & Claypool Life Science.

This article on a gene on human chromosome 16 is a stub. You can help Wikipedia by adding missing information.

[refGRCh38Ensembl-1] 1 2 3 ENSG00000285346 GRCh38: Ensembl release 89: ENSG00000168925, ENSG00000285346 – Ensembl, May 2017

[refGRCm38Ensembl-2] 1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000031957 – 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.

[entrez-5] 1 2 3 4 5 "Entrez Gene: Chymotrypsinogen B1". Retrieved 2026-09-01.

[6] "P17538 · CTRB1_HUMAN". uniprot.org. UniProt consortium. Retrieved 2026-09-01.

[pandol2010-7] Pandol SJ (2010). "Anatomy". The Exocrine Pancreas. Morgan & Claypool Life Science.