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Further Characterization of an Enkephalin‐Generating Enzyme from Adrenal Medullary Chromaffin Granules
Author(s) -
Lindberg I.,
Yang H.Y. T.,
Costa E.
Publication year - 1984
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1984.tb02802.x
Subject(s) - proenkephalin , chemistry , enkephalin , enzyme , adrenal medulla , biochemistry , size exclusion chromatography , peptide , protease , opioid peptide , endocrinology , biology , opioid , catecholamine , receptor
An adrenomedullary protease capable of generating Met 5 ‐enkephalin from endogenous precursor(s) has been purified 1,000‐fold using affinity chromatog‐raphy in combination with gel filtration. This trypsin‐like enzyme has an apparent molecular weight of 20,000 dal‐tons by gel filtration. The reactivity of the enzyme toward several fluorogenic peptides, Peptides E and F, and the heptapeptides, Met 5 ‐enkephalin‐Arg 6 ‐Phe 7 and Met 5 ‐en‐kephalin‐Arg 6 ‐Arg 7 , was examined. The two heptapeptides and the fluorogenic compounds were poor substrates for the adrenal enzyme; in contrast, Peptides E and F were cleaved. The low molecular weight products of Peptide F digestion were identified by HPLC as Arg 1 ‐Met 6 ‐enkephalin, Met 5 ‐enkephalin, and Met 5 ‐enkephalin‐Lys 6 , while digestion of Peptide E resulted in the production of Leu 5 ‐enkephalin and Met 5 ‐enkephalin‐Arg 6 ‐Arg 7 . [ 3 H]‐β m ‐Lipotropin was not hydrolyzed by the adrenal enzyme. These results indicate that this adrenomedullary protease is capable of cleaving adrenal opioid peptides at the paired basic sites and thus represents a possible candidate for a proenkephalin‐converting enzyme.