Pyrrolidonyl Peptidase in Bacteria. The Enzyme from Bacillus subtilis

The synthesis of l-pyrrolidonyl-α- and β-naphthylamides has been described. The β-naphthylamide was used for the colorimetric determination of pyrrolidonyl peptidase activity. This enzyme was purified from Bacillus subtilis by precipitation with ammonium sulphate, using a DEAE-cellulose column and finally on a Sephadex G-200 column. The activity of the purified enzyme preparation was 530-fold that of the crude homogenate. No other peptidase activity in this preparation was found. It was demonstrated that the enzyme liberates pyrrolidonecarboxylic acid from human seromucoid. The results obtained suggest that pyrrolidonyl peptidase is an SH-enzyme. The occurrence of the enzyme in some groups of gram-positive and gram-negative bacteria was noted.