Purification and partial amino acid sequence of a bovine cartilage-derived collagenase inhibitor.

An inhibitor of mammalian collagenase from bovine scapular cartilage has been purified to homogeneity. The inhibitor, extracted from cartilage using 2 M NaCl, was applied to an A-1.5m gel filtration column. Inhibitor eluted at an apparent Mr of 28,000. Further purification was achieved by ion exchange chromatography, gel filtration, and reverse-phase high performance liquid chromatography. A purification of greater than 1,000-fold was achieved. The inhibitor was judged homogeneous by the appearance of a single band on a silver-stained 15% sodium dodecyl sulfate-polyacrylamide gel. Reduced inhibitor had an Mr of 27,400, unreduced inhibitor had an Mr of 23,900. NH2-terminal sequence data were obtained for the first 45 residues. The bovine cartilage-derived inhibitor exhibits greater than 65% homology over the first 23 residues with a collagenase inhibitor purified from human skin fibroblasts maintained in cell culture. This is the first demonstration that collagenase inhibitors extracted directly from tissue may be similar to those obtained from culture medium.