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An aminopeptidase activity in bovine pituitary secretory vesicles that cleaves the N‐terminal arginine from β‐lipotropin 60–65
Author(s) -
Gainer Harold,
Russell James T.,
Loh Y.Peng
Publication year - 1984
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(84)80586-4
Subject(s) - pepstatin , leupeptin , phenylmethylsulfonyl fluoride , arginine , biochemistry , aminopeptidase , chemistry , chymotrypsin , enzyme , cathepsin h , vesicle , biology , cathepsin b , endocrinology , medicine , pmsf , protease , amino acid , trypsin , membrane , leucine
Secretory vesicles isolated from the neural and intermediate lobes of the bovine pituitary contained a membrane‐bound aminopeptidase activity which cleaved arginine from β‐LPH 60–65 (Arg‐Tyr‐Gly‐Gly‐Phe‐Met) and Arg‐MCA. Neither methionine enkephalin (Tyr‐Gly‐Gly‐Phe‐Met) nor Substance P, which has an N‐terminal arginine followed by a proline, could serve as substrates for this aminopeptidase activity; nor could cathepsin B‐like or chymotrypsin‐like enzyme activities be detected in the vesicle preparations. Maximal enzyme activity was at pH 6.0, and the activity was inhibited by EDTA, stimulated by Co 2+ and Zn 2+ , but was unaffected by leupeptin, pepstatin A, phenylmethylsulfonyl fluoride and p ‐chloromercuribenzenesulfonate, suggesting that the enzyme is a metalloaminopeptidase. The presence of this aminopeptidase activity in secretory vesicles suggests that it may be involved in peptide prohormone processing.