Generation of matrix-degrading proteolytic system from fibronectin by cathepsins B, G, H and L.

ABSTRACT

By their endoproteinase activities, cathepsins B, G, H and L can generate matrix-degrading proteolytic system from fibronectin. All four cathepsins studied cleaved fibronectin in fragments that were either proteolytically active or activated after incubation at pH 7.4 and in the presence of Ca2+. The highest enhancement of the matrix protein-degrading activity was observed after a gelatin-affinity chromatography of each digest. These results suggest that the effect of cathepsins at physiological pH in vivo may be enhanced by the activation of a matrix-degrading proteolytic system from fibronectin.