It has been reported that several metalloproteases degrade the matrix component in enamel development. However, no reports are available for the dentin matrix protease except collagenase. The purpose of this experiment was to extract and characterize the metalloprotease from dentin. Human dentin powder was immersed in PBS (pH 7.4) for 12 hours at 4°C, and then the extracts were applied on SDS-PAGE and enzymography. The results obtained were as follows: 1. Several proteases were extracted from

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... man dentin. The approximate molecular weight of the 59 KDa protease (59 K P-ase) showed the major enzymatic activity on gelatin and casein enzymogram. 2. 59 K P-ase was partially purified by using the heparin and gelatin affinity columns. 3. The optimum pH of 59 KP-ase was nine. 4. The activity was inhibited by EDTA and to a lesser degree by PMSF. 5. Osteopontin was cleaved by 59 K P-ase. From these results, we conclude that 59 K P-ase is a phosphoprotein protease and plays an important role in dentin matrix development or degradation process.