Extraction of latent-type collagenase from cultured bovine dental pulps with NaCl or urea or by collagen degradation.

All of the collagenase activity extracted from cultured bovine dental pulp tissue with NaCl or urea solutions was due to enzyme in a latent form and identified as a typical animal collagenase. Isotonic sucrose solution solubilized no detectable collagenase activity from cultured dental pulps. Also, no collagenase activity was extracted from either fresh bovine dental pulps or those cultured in Tyrode's solution containing 50 micrograms/ml cycloheximide. A two-day difference was observed between the appearance of collagenase activity in the cultured pulps and in the culture medium. The activity profiles in the culture media showed essentially no difference with or without the addition of cyclohexamide on and after the 10th day of culture, indicating that the biosynthesis of collagenase in the cultured pulp might have terminated around that time. About 80% of the total pulp collagenase activity was extracted by a bacterial collagenase procedure. Nearly half (43.5%) of the collagenase activity extracted from the cultured pulps with NaCl or urea solution was precipitated with collagen molecules in the presence NaCl, and most of the precipitated activity retained in the precipitate even after washing it with NaCl-buffer solution. These facts suggest a close association of collagenase with the collagen in cultured dental pulp tissue.