title: A new serine protease which preferentially recognizes p-guanidino-L-phenylalanyl residue in ascitic plasma from Ehrlich ascites tumor-bearing mice.
abstract: A new enzyme which hydrolyzes anilide substrates of p-guanidino-L-phenylalanine in preference to those of arginine was found in the ascitic plasma from Ehrlich ascites tumor-bearing mice. The activity of this enzyme on N alpha-benzyloxycarbonyl-p-guanidino-L-phenylalanine p-nitroanilide was strongly inhibited by diisopropyl fluorophosphate and phenylmethanesulfonyl fluoride but not by sulfhydryl-reactive reagents and metal chelating agents. Peptide substrates containing p-guanidino-L-phenylalanine were hydrolyzed by this enzyme much faster than those containing arginine. These results suggest that this enzyme is a different type of serine protease from trypsin and thrombin. This enzyme was also found in the human gastric and colon cancer cells and their surrounding ascitic plasmas.
mesh_terms: D000818:Animals; D001120:Arginine; D001201:Ascites / Q000201:enzymology; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism*; D010450:Endopeptidases / Q000378:metabolism*; D005260:Female; D051379:Mice; D010649:Phenylalanine / Q000031:analogs & derivatives; D011480:Protease Inhibitors; D012697:Serine Endopeptidases; D013379:Substrate Specificity
chemical_list: D011480:Protease Inhibitors; C017351:4-guanidinophenylalanine; D010649:Phenylalanine; D001120:Arginine; D010450:Endopeptidases; D012697:Serine Endopeptidases