Post-secretory processing of regulatory peptides: the pancreatic polypeptide family as a model example.

Post-secretory metabolism is an important event in the overall homeostasis of regulatory peptides and the enzymes involved in these processes may be suitable targets for pharmacological intervention. Some examples are reviewed here. Peptide YY and neuropeptide Y, both members of the pancreatic polypeptide family, can be processed by dipeptidyl peptidase IV to their (3-36) fragments by removal of the N-terminal Tyr-Pro dipeptide, which generates a metabolite of different receptor selectivity. Aminopeptidase P and endopeptidase-24.11 also metabolize these peptides and the relative levels of these three cell-surface enzymes may regulate their interconversion between receptor-selective forms and inactive metabolites.