PROTEOLYTIC ACTIVITY OF TREPONEMES FROM THE SUBGINGIVAL PLAQUE OF PERIODONTITIS PATIENTS

The proteolytic activities of whole cells and extracts of sonicated ce lls from Treponema denticola ATCC 35405, T vincentii ATCC 35580, T. so cranskii ATCC 35536 and seven clinical isolates of T. denticola were c ompared using early stationary phase cultures. Synthetic bacterial col lagenase substrates (FALGPA: furylacryloyl-L-leucyl-glycyl-L-prolyl-D- arginine and PZ-PLGPA: onyl-L-prolyl-L-leucyl-glycyl-L-prolyl-D-argini ne) were hydrolysed by all Treponema extracts. Soluble type I collagen and reconstituted [H-3]collagen were slowly hydrolysed by extracts fr om T. denticola and T. vincentii but not that from T. socranskii The e xtracts of T. denticola ATCC 35405 and most clinical isolates of T. de nticola readily hydrolysed gelatin and collagen-derived polypeptides. Slow or no hydrolysis of these substrates was observed for T. vincenti i and T. socranskii. Soluble type I collagen, gelatin and the collagen -derived peptides were hydrolysed by whole cells of T. denticola ATCC 35405 but not by those of T. vincentii and T socranskii. The proteolyt ic activities of the Treponema-extracts towards the synthetic collagen ase substrates appeared not to be affected by the growth rate or the g rowth phase of the cells, but the aminopeptidase and iminopeptidase ac tivities (substrates: N-aminoacyl-2-naphthylamines of arginine and pro line) varied during growth. A labile, apparently membrane-associated, low-molecular weight FALGPA-hydrolysing protease was partially purifie d from T. denticola ATCC 35405. The enzyme degraded soluble type I col lagen, synthetic collagen substrates, gelatin and collagen-derived pol ypeptides. The enzyme retained its activity in extracellular condition s and it was activated by a heat-denaturable factor (M(W)>30 000) pres ent in the rat inflammatory exudate. The pH optimum of the enzyme was at approximately pH 7.5. Thus, T. denticola appeared to possess protea ses which hydrolysed substrates representing both early and late stage s of collagen breakdown and which may be active in conditions existing in the crevicular fluid.