Regulation of carboxypeptidase H by inhibitory and stimulatory mechanisms during neuropeptide precursor processing.

1. Carboxypeptidase H is one of several proteolytic processing enzymes required for conversion of large neuropeptide precursors into the small peptide neurotransmitters and hormones. 2. Because of the importance of posttranslational processing as a regulatory step for the production of active peptides, recent studies investigating control mechanisms for carboxypeptidase H (CPH) are reviewed. 3. Evidence is discussed which illustrates how CPH can be inhibited and activated. These findings suggest that a processing enzyme can play a role in the control of neuropeptide production. 4. It will be important in further studies to understand how the multiple processing enzymes--endopeptidase(s) and aminopeptidase, along with CPH--are coordinately regulated for the synthesis of active peptides.