proMMP7 (proMatrilysin-1) activation by trypsin occurs via an intermediate cleaved at Lys50-Asn51 which undergoes autocatalysis (Crabbe et al. 1992). Leukocyte elastase and plasmin partially activate MMP7 by an uncharacterized mechanism. Highly sulfated glycosaminoglycans (GAG), such as heparin, chondroitin-4,6-sulfate (CS-E), and dermatan sulfate, markedly enhance (>50-fold) the intermolecular autolytic activation of promatrilysin and the activity of fully active matrilysin (Ra et al. 2009).