Isolation and characterization of a peptidase from an oral strain of Corynebacterium matruchotii.

From the cell extract of Corynebacterium matruchotii strain ATCC 14266, a peptidase could be isolated and purified, increasing the specific activity 267 times. This enzyme with a molecular weight of 60,000 was completely inactivated by heating at 50 degrees C for 20 min, its optimum pH was found to be pH 7.5 and the isoelectric point was 4.1. The peptidase was inhibited by diisopropylfluorophosphate, phenylmethanesulfonyl fluoride, tosyl-L-lysine chloromethyl ketone, chymostatin and urea. Among various synthetic substrates tested, only benzoyl-L-arginine-p-nitroanilide and benzoyl-L-arginine ethylester were found to be hydrolyzed by this enzyme. Several proteins investigated were not hydrolyzed, but the enzyme inactivated a peptidic staphylococcal bacteriocin.