Carboxypeptidase D (CPD)

The pancreatic carboxypeptidase-like and the regulatory B-type carboxypeptidase subfamilies. Carboxypeptidase D has been identified as a regulatory B-type carboxypeptidase. CPD is a homolog of duck gp180, a hepatitis B virus-binding protein. Transcript variants utilizing alternative polyadenylation signals exist for this gene.The predicted 1,377-amino acid protein contains a signal sequence, 3 tandem carboxypeptidase homology domains, and a C-terminal putative transmembrane domain. The 3 carboxypeptidase domains have sequence similarity to the regulatory B-type carboxypeptidase family. Overall, the amino acid sequences of CPD and gp180 are 75% identical. Northern blot analysis revealed CPD expression as multiple mRNAs in pancreas, placenta, heart, and skeletal muscle.