title: Topology and some properties of the renal brush border membrane-bound peptidase(s) participating in the metabolism of S-carbamidomethyl glutathione.
abstract: Topological features and some properties of the membrane-bound peptidase(s) participating in the metabolism of a glutathione S-conjugate in the kidney were studied. S-Carbamidomethyl glutathione, a model compound for glutathione S-conjugate, was demonstrated to be sequentially hydrolyzed by gamma-glutamyltransferase (5-glutamyl)-peptide:amino-acid 5-glutamyltransferase; EC 2.3.2.2) and peptidase(s) bound to rat renal brush border membrane vesicles. Hydrolysis of S-carbamidomethyl cysteinylglycine was found to be inhibited by 1,10-o-phenanthroline, suggesting a participation of a metal-requiring peptidase in this process. The hydrolytic activity of the membranous peptidase was markedly depressed by cysteinylglycine S-acetyldextran polymer (molecular weight, 500 000), a nonpermeating derivative for cysteinylglycine. Papain treatment of brush border membrane vesicles resulted in the solubilization of most hydrolytic activity toward S-carbamidomethyl cysteinylglycine. Amino-peptidase M was also solubilized from the membrane and the increase in the specific activity of this enzyme in the papain-soluble fraction was in parallel within that of the peptidase activity for hydrolysis of S-carbamidomethyl cysteinylglycine. The hydrolytic activity of purified brush border membrane vesicles toward S-carbamidomethyl glutathione was fully reconstituted by the combined use of purified gamma-glutamyltransferase and aminopeptidase M. These findings indicated that, as in the case of the cleavage of gamma-glutamyl linkage of glutathione and related compounds, hydrolysis of the S-substituted cysteinylglycine occurred exclusively on the lumenal surface of renal brush border membrane as catalyzed mainly by aminopeptidase M.
mesh_terms: D000626:Aminopeptidases / Q000378:metabolism; D018826:CD13 Antigens; D002458:Cell Fractionation; D003980:Diazooxonorleucine / Q000494:pharmacology; D004150:Dipeptidases / Q000378:metabolism; D005978:Glutathione / Q000031:analogs & derivatives* / Q000378:metabolism; D007668:Kidney / Q000201:enzymology*; D008566:Membranes / Q000201:enzymology; D008861:Microsomes / Q000201:enzymology; D008871:Microvilli / Q000201:enzymology; D010447:Peptide Hydrolases / Q000378:metabolism*; D010618:Phenanthrolines / Q000494:pharmacology; D005723:gamma-Glutamyltransferase / Q000378:metabolism
chemical_list: D010618:Phenanthrolines; D003980:Diazooxonorleucine; C031766:S-carbamidomethylglutathione; D005723:gamma-Glutamyltransferase; D010447:Peptide Hydrolases; D000626:Aminopeptidases; D018826:CD13 Antigens; D004150:Dipeptidases; D005978:Glutathione; C025205:1,10-phenanthroline