title: Proenkephalin processing enzyme with specificity toward paired basic residues purified from bovine adrenal chromaffin granules.
abstract: A novel protease exhibiting substrate specificity toward paired basic residues has been partially purified from the soluble fraction of bovine adrenal chromaffin granules by utilizing an affinity chromatography on STI-Sepharose. The enzyme, with optimal pH around 7.5-9.5, is classified into a serine-protease by its inhibitor spectrum. The enzyme specifically cleaved the Lys-Arg bonds of two synthetic peptides containing the subsequence of proenkephalin A, but endogenous opioid peptides containing a single basic residue in the molecule [Met)enk-Arg-Phe, (Met)enk-Arg-Gly-Leu) were not affected by the enzyme. The unique substrate specificity of the enzyme, which is well in accord with the processing pattern of proenkephalin A in adrenal medulla, indicates that the enzyme may be physiologically involved in proenkephalin processing.
mesh_terms: D000313:Adrenal Medulla / Q000201:enzymology*; D000818:Animals; D002417:Cattle; D002837:Chromaffin Granules / Q000201:enzymology*; D002838:Chromaffin System / Q000201:enzymology*; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D010450:Endopeptidases / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D008666:Metalloendopeptidases
chemical_list: D010450:Endopeptidases; D008666:Metalloendopeptidases; C022510:thimet oligopeptidase