Purification and properties of a proline iminopeptidase from Propionibacterium acnes.

Proline iminopeptidase was extracted from the cells of a strain of Propionibacterium acnes and purified. The molecular weight was estimated to be about 120,000 by SDS-polyacrylamide gel electrophoresis. The enzyme showed the highest activity at 50 degrees C-55 degrees C and its optimum pH was found at 7.5-8.0. The enzyme activity was inhibited by p-chloromercuribenzoate, indicating that this peptidase is a SH-enzyme. Especially prolyl-glycyl-glycine but also prolyl-proline bonds were hydrolyzed by this enzyme, glycyl-proline was not split.