IDENTIFICATION IN RAT SKIN AND SUBCUTANEOUS GRANULOMA OF AN ENZYME LIBERATING N-TERMINAL GLYCYL-PROLINE FROM PEPTIDES

A peptidase capable of liberating glycyl-proline dipeptide from glycyl-proline naphthylamide, glycyl-prolyl-alanine and from glycyl-prolyl-alanyl-alanine was partially separated from enzymes hydrolysing leucine naphthylamide by subjecting rat skin homogenate to chromatography on DEAE-cellulose. The enzyme was found to be optimally active at pH 7.5 and not to require any easily dissociable cofactors or to be dependent on sulphydryl groups. A similar enzyme was found in subcutaneous foreign-body granuloma tissue. Azo colour was seen mainly in fibroblasts when using diazo coupling reaction for histochemical localization of the enzyme. © 1969 Springer-Verlag.