A 92 KDA GELATINASE (MMP-9) CLEAVAGE SITE IN NATIVE TYPE-V COLLAGEN

Native type V collagen molecules resist mammalian collagenase but are cleaved by certain gelatinases. We report a prominent site of cleavage within the collagen type V molecules by 92 kDa gelatinase (MMP-9). Th e enzyme was purified from conditioned medium of a rabbit synovial cel l line (HIG-82). It cleaved native type V collagen from bovine bone in solution at two molecular sites, one near the amino-terminus, the oth er producing a 3/5 C-terminal fragment. Amino-terminal sequence analys is of the individual alpha chains from this latter fragment showed tha t MMP-9 had cleaved between residues Gly439-Val in both alpha 1(V) and alpha(XI) and between residues Gly445-Leu in the alpha 2(V) chain. Th ese sites are close to the previously reported trypsin-cleavage site. The findings imply that gelatinases may be necessary for initiating or completing degradation of type I/type V copolymeric fibrils for growt h and remodeling of extracellular collagen. (C) 1994 Academic Press, I nc.