title: Purification and properties of a pepstatin-insensitive carboxyl proteinase from a gram-negative bacterium.
abstract: A carboxyl proteinase was found in the culture filtrate of a Gram-negative bacterium. The optimum for the action of the purified enzyme was approx. pH 3 and its caseinolytic activity was not inhibited by carboxyl proteinase inhibitors, such as pepstatin, Streptomyces pepsin inhibitor and diazoacetyl-DL-norleucine methyl ester. 1,2-epoxy-3-(p-nitrophenoxy)propane modified the enzyme with concomitant loss of its enzyme activity. The enzymatic and physicochemical properties of the enzyme were compared with those of known pepstatin- and diazoacetyl-DL-norleucine methyl ester-insensitive carboxyl proteinases previously reported. To our knowledge, this is the first carboxyl proteinase isolated from bacteria.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D016282:Aspartic Acid Endopeptidases; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004352:Drug Resistance, Microbial; D010450:Endopeptidases / Q000302:isolation & purification*; D006090:Gram-Negative Bacteria / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D009842:Oligopeptides / Q000494:pharmacology*; D010436:Pepstatins / Q000494:pharmacology*; D011480:Protease Inhibitors / Q000494:pharmacology; D013696:Temperature
chemical_list: D000596:Amino Acids; D009842:Oligopeptides; D010436:Pepstatins; D011480:Protease Inhibitors; C014195:Streptomyces pepsin inhibitor; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C031375:pepstatin