RAT DIPEPTIDYL-PEPTIDASE-IV (DPP-IV) EXHIBITS ENDOPEPTIDASE ACTIVITY WITH SPECIFICITY FOR DENATURED FIBRILLAR COLLAGENS

Dipeptidyl peptidase IV (DPP IV, CD 26) is an integral membrane serine protease exhibiting a well characterized esopeptidase activity. The p resent study shows that DPP IV also possesses a novel gelatinase activ ity and therefore endopeptidase activity, which was directly demonstra ted by gelatin zymography. Protease inhibitor profile analysis showed that the endo-and esopeptidase activities of DPP IV share a common act ive site. Substrate specificity was detected for denatured collagen ty pes I, II, III and V suggesting that DPP IV might contribute to collag en trimming and metabolism. On the basis of these data we propose that DPP IV and the recently sequenced gelatinolytic seprase (FAP alpha) r epresent a new subfamily of gelatinolytic integral membrane serine pro teases. (C) 1998 Federation of European Biochemical Societies.