Partial purification and characterization of a neutral proteinase with collagen telopeptidase activity produced by human gingival fibroblasts.

A neutral proteinase was purified 1930-fold from medium conditioned by the culture of human gingival fibroblasts that had been stimulated to secrete enzymes by concanavalin A. This enzyme had an apparent molecular weight of 35,000 (gel chromatography) and apparent isoelectric point of 4.3 (chromatofocusing). It was inhibited by chelating agents, serum, and nonactivated conditioned fibroblast medium, but not by phenylmethylsulphonyl fluoride or N-ethylmaleimide. This proteinase removes the C-telopeptide from the alpha 1 chain of type I collagen, an activity which could be important in the degradation of collagen in the extracellular matrix. It was also found to digest fibronectin but had no effect on proteodermatan sulphate under the conditions used. It appears to be unrelated to previously described fibroblast extracellular proteinases and we, therefore, tentatively propose the name fibroblast metalloproteinase IV.