Prolyl endopeptidase

Prolyl endopeptidase (E.C. 3.4.21.26) an Enzyme previously called post proline cleaving Enzyme, TRH-deamidase or kininase B, may play a role in neuropeptide metabolism. This Enzyme, highly active in brain and Other tissues, catabolizes proline-containing Peptides such as substance P, neurotensin, luteinizing hormone-releasing hormone, thyrotropin releasing hormone, bradykinin and angiotensin II. The structure of beta-neo-endorphin suggests that this opioid peptide is formed by the action of prolyl endopeptidase on a precursor of higher molecular weight. Formation of two biologically active fragments of substance P also requires the action of this Enzyme. This review summarizes the current knowledge of the biochemistry of this Enzyme, and its potential significance for neuropeptide physiology and pharmacology.