Purification of the neutral proteoglycan-degrading metalloproteinase from human articular cartilage tissue and its identification as stromelysin matrix metalloproteinase-3.

The 'neutral' proteoglycan-degrading metalloproteinase of human articular cartilage was purified 3,500-fold by use of an anti-(matrix metalloproteinase-3) immunoglobulin G affinity column. Molecular masses of the latent and multiple active forms and specificity of action on casein, transferrin, gelatin and fibronectin were identical with those of authentic stromelysin (matrix metalloproteinase-3) from cultured human rheumatoid synovial fibroblasts. The optimum pH of this proteinase on proteoglycan monomer was pH 5.5, and on Azocoll, 6.2; digestion of fibronectin and gelatin was more extensive at pH 5.5 than at 7.5.