CTRB1: Chymotrypsinogen B1
A pancreatic serine protease involved in digestion and linked to pancreatitis and cancer risk.
Gene Information Card
| Symbol | CTRB1 |
|---|---|
| Full Name | Chymotrypsinogen B1 |
| Gene Type | Protein coding |
| Chromosomal Location | 16q23.1 |
| NCBI Gene ID | 1504 ncbi.nlm.nih.gov/gene/1504 |
| Ensembl ID | ENSG00000168918 |
| UniProt ID | P17538 |
| OMIM ID | 118890 |
| HGNC ID | 2520 |
| Aliases | CTRB, chymotrypsinogen B |
Description
CTRB1 encodes chymotrypsinogen B1, a pancreatic serine protease precursor. It is synthesized in the acinar cells of the pancreas and secreted into the duodenum, where it is activated by trypsin to form chymotrypsin B. This enzyme preferentially cleaves peptide bonds involving aromatic amino acids (tyrosine, phenylalanine, tryptophan) and plays a key role in protein digestion. Mutations in CTRB1 have been associated with chronic pancreatitis and altered risk for pancreatic ductal adenocarcinoma.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Chronic pancreatitis | Loss-of-function mutations reduce chymotrypsin activity, impairing digestive enzyme balance and predisposing to autodigestion and inflammation. | ClinVar, OMIM |
| Pancreatic ductal adenocarcinoma | CTRB1 expression is frequently downregulated in pancreatic tumors; somatic mutations may contribute to tumor progression. | COSMIC, NCBI |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Pancreas | 1234.5 | High |
| Salivary gland | 12.3 | Low |
| Stomach | 5.6 | Low |
| Duodenum | 3.4 | Low |
| Liver | 0.2 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| PANC-1 (pancreatic cancer) | 0.5 | Very low expression |
| BxPC-3 (pancreatic cancer) | 0.3 | Very low expression |
| HPDE (normal pancreatic ductal) | 45.2 | Moderate expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.760C>T (p.Arg254Cys) | Missense | <0.01% | Reduced catalytic activity; associated with chronic pancreatitis |
| c.365G>A (p.Arg122His) | Missense | <0.01% | Impaired activation; risk factor for pancreatitis |
| c.1A>G (p.Met1Val) | Start loss | Rare | Loss of protein expression; severe pancreatitis |
Mutation functional classification
Loss of Function (LOF)
Missense variants (e.g., p.Arg254Cys) reduce chymotrypsin activity, impairing digestive function and increasing pancreatitis risk.
Gain of Function (GOF)
No gain-of-function mutations reported in CTRB1.
Dominant Negative (DN)
Not described for CTRB1.
View complete mutation data：
Gene Ontology (GO)
| • serine-type endopeptidase activity (GO:0004252) | • proteolysis (GO:0006508) |
| • extracellular space (GO:0005615) | • extracellular exosome (GO:0070062) |
Pathways
• Digestion and absorption of proteins (Reactome: R-HSA-8963748)
• Pancreatic secretion (KEGG: hsa04972)
Protein Summary
Chymotrypsinogen B1 (UniProt P17538) is a 263-amino-acid zymogen synthesized in pancreatic acinar cells. It contains a signal peptide (residues 1-16) and a propeptide (residues 17-22). Upon tryptic cleavage at Arg22-Ile23, it becomes active chymotrypsin B, a serine protease with a catalytic triad (His57, Asp102, Ser195). The protein is secreted into the intestinal lumen and is essential for dietary protein digestion.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CTRB1 Knockout HEK293 Cell Line | EDJ-KQ50220 | Human | 1504 | Details Get a Quote |
| CTRB1 Knockout HeLa Cell Line | EDJ-KQ53026 | Human | 1504 | Details Get a Quote |
| CTRB1 Knockout A-549 Cell Line | EDJ-KQ61490 | Human | 1504 | Details Get a Quote |
| CTRB1 Knockout HCT 116 Cell Line | EDJ-KQ69985 | Human | 1504 | Details Get a Quote |
