CTRB1 Human

The CTRB1 gene is located on chromosome 16 and is closely related to the CTRB2 gene . The gene encodes a preproprotein that is processed to produce the mature enzyme. The mature protein consists of 263 amino acids and includes a signal peptide (1-18) and three chains: Chymotrypsin B chain A (19-31), Chymotrypsin B chain B (34-164), and Chymotrypsin B chain C (167-263) .

CTRB1 is predominantly expressed in the pancreas, specifically in the acinar cells . It is secreted into the gastrointestinal tract as an inactive precursor, chymotrypsinogen, which is then activated in the small intestine .

The primary function of CTRB1 is to aid in the digestion of proteins in the small intestine. As a serine protease, it cleaves peptide bonds in proteins, facilitating their breakdown into smaller peptides and amino acids . This enzymatic activity is crucial for the proper digestion and absorption of dietary proteins.

The activation of chymotrypsinogen to chymotrypsin is tightly regulated. This process is initiated by the enzyme trypsin, which cleaves specific peptide bonds in chymotrypsinogen to produce the active enzyme . This regulatory mechanism ensures that chymotrypsin is activated only in the appropriate location, preventing potential damage to the pancreas and other tissues.

Mutations or dysregulation of the CTRB1 gene have been associated with various diseases, including chronic pancreatitis . Additionally, some human populations have an alternate haplotype that inverts a region containing portions of the CTRB1 and CTRB2 genes, leading to differential gene expression and increased risk for chronic pancreatitis .

Recombinant human chymotrypsinogen-B1 is produced using various expression systems, including human cells, yeast, and E. coli . The recombinant protein is often tagged with a polyhistidine tag for purification purposes and is used in research to study its structure, function, and potential therapeutic applications .