Carboxypeptidase B1 (CPB1)

Carboxypeptidase B1 (CPB1) is a pancreas-enriched metallocarboxypeptidase enzyme encoded by the CPB1 gene, secreted as an inactive proenzyme and activated in the small intestine by trypsin[1][3][5][7]. It specifically cleaves basic amino acids—arginine and lysine—from the C-terminal end of peptides and proteins, contributing to the final steps of dietary protein digestion[1][3][5]. It is highly specific to pancreatic acinar cells and is a valuable serum biomarker for acute pancreatitis and pancreatic graft dysfunction but is generally not elevated in pancreatic carcinoma[5][7]. Disease-associated genetic variants of CPB1 can disrupt its secretion, induce endoplasmic reticulum stress, and are linked to increased risk of pancreatic cancer[4]. Altered phosphorylation of CPB1 in pancreatic β-cells is implicated in mechanisms of pancreatic regeneration and may affect β-cell proliferation, suggesting possible roles beyond digestive function[2]. CPB1 is not currently a routine therapeutic target, but its biological and disease associations make it relevant in diagnostic and research contexts.

Other names

Carboxypeptidase BCPBPCPBPASPPancreas-specific proteinPancreatic carboxypeptidase BTissue carboxypeptidase BProtaminaseProcarboxypeptidase B

Not targeted pharmacologically; indirect implication in disease is via genetic variants causing ER stress or altered phosphorylation states (affecting β-cell proliferation)[2][4].