Fig. 5.

Proteolytic digestion by Lys-C or cathepsin K shows expected cleavage pattern. a Lys-C incubation with purified type II procollagen shows a reduction in protein size, as seen by silver staining, consistent with removal of N- and C-propeptides. b Western blot with an antibody specific to the N-telopeptide shows that shorter incubation times result in the removal of propeptide but not telopeptides, while longer incubations result in cleavage of the N-telopeptide by Lys-C. c Western blot showing increasing time-dependent cleavage of type II collagen (prepared by chymotrypsin digestion of procollagen) by recombinant cathepsin K