Investigation of proteases responsible for degradation of periodontal tissue by periodontopathogens

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1.Elastolytic enzyme of prevotella intermediaElastolytic strains of Prevotella intermedia were isolated from pus samples of adult periodontal lesions. Elastase was found to associate with envelope, and it could be solubilized with guanidine-HCl. The enzyme was purified to homogeneity by sequential procedures including ion-exchange chromatography, gel filtration, and hydrophobic interaction chromatography. This elastase was a serine protease, and its mass was 31 kDa. It hydrolyzed elastin powder, but collagen and azodye-conjugated proteins were not degraded by this enzyme. Both synthetic substrates for human pancreatic (glutaryl-Ala-Ala-Pro-Leu P-nitroanilide) and leukocyte elastase (methoxy succinyl-Ala-Ala-Pro-Val p-nitroanilide) were hydrolyzed.Protease of Eubacterium like organismFrom the dental plaque samples of periodontal patients, we isolated anaerobic strains displaying proteolytic activity against succiny-Ala-Ala-Pro-Phe P-nitroanilide (chymotrypsin substrate) and gelatin. However, this proteolysis was observed only when the organisms were cultured in the media supplemented with whole blood. The protease of such strains may be stimulated or induced by component(s)of blood. These strains were anaerobic gram-positive rods and were found in half the examined plaque samples. Their common properties were as follows : nogative in production of catalase and indole, nitrate reduction, esculin hydrolysis, and fermentation of glucose and lactose. Acetic acid was detected as a metabolic product. These findings suggest that the isolates resemble nonsaccharoclastic Eubacterium. The effect of blood on protease production could be substituted for serum, serum albumin, and saliva. The purified protease hydrolyzed glutary-Ala-Ala-Pro-Leu p-nitroanilide and azocoll as well as the chymotrypsin substrate described above and gelatin. Its mass was 150 kDa and the activity was inhibited by phenylmethylsulfonyl-fluoride, indicating this enzyme is a serine protease.