Carboxypeptidase D


Carboxypeptidase D can refer to one of several enzymes. A family of serine carboxypeptidases includes is an enzyme. This enzyme has an optimal pH of 4.5-6.0, is inhibited by diisopropyl fluorophosphate, and catalyses the following chemical reaction
A completely distinct enzyme has also been named carboxypeptidase D. This second enzyme is a metallocarboxypeptidase and is broadly expressed in mammalian tissues. Like the serine carboxypeptidase, the metallocarboxypeptidase D also removes C-terminal arginine or lysine residues from peptides, with an optimal pH range of 5 to 7. Metallocarboxypeptidase D is located in the trans Golgi network where it contributes to the biosynthesis of neuropeptides and peptide hormones along with carboxypeptidase E. In addition to this role, metallocarboxypeptidase D contributes to the processing of proteins, following the action of furin. The duck ortholog of metallocarboxypeptidase D was named gp180 and is a receptor for uptake of duck hepatitis B virus. In fruit fly, carboxypeptidase D is known as the silver mutation, with defects causing altered wing shape. Metallocarboxypeptidase D is generally a membrane-bound protein, although in some organisms a soluble form is generated by either differential RNA splicing or by proteolytic activity. In the scientific literature, most of the published articles using the name "Carboxypeptidase D" in the title refer to metallocarboxypeptidase D and not the serine carboxypeptidase.