DEGRADATIVE ENZYMES OF ORAL STREPTOCOCCI

Members of the Streptococcus sanguis group (SSG) and Streptococcus mil leri group (SMG) were screened for their ability to produce glycosidas e, arylamidase (peptidase), protease, dextranase and glycosyltransfera se activities. Species within each group produced unique patterns of a ctivity. The most commonly produced glycosidases were beta-D-glucosida se, beta-D-galactosidase, N-acetyl-beta-D-glucosaminidase and N-acetyl -beta-D-galactosaminidase and the least commonly produced glycosidase activity was beta-fucosidase with Streptococcus intermedius (SMG) bein g the only species capable of producing the activity. For arylamidase activity, the most commonly produced type was lysine-arylamidase, Glyc osidase and arylamidase activities were localized to particular sub-ce llular fractions. alpha-galactosidase was found only in culture supern atant fluids whereas N-acetyl-beta-D-glucosaminidase was found in all fractions; the culture supernatant, cell wail, cell membrane and cytop lasm. No arylamidase activity was seen in culture supernatants. Phe-ar g-arylamidase was found only in cytoplasmic fractions whereas val-pro- argarylamidase was found in cell walls, cell membranes and cytoplasmic fraction. Protease activity was measured as the degradation of bovine serum albumin (BSA) and casein. Casein was degraded by a number of st rains whereas no species/strains were able to degrade BSA. Streptococc us intermedius, Streptococcus constellatus (SMG), Streptococcus mitior and Streptococcus defectivus (SSG) were the only species that produce d hyaluronidase and no species produced chondroitin sulphatase. The gr oups were also examined for their abilities to produce glycosyltransfe rase and dextranase. Strep. sanguis, Streptococcus gordonii, Streptoco ccus mitis and Streptococcus oralis produced glucosyltransferase and, with the exception of the latter species, fructosyltransferase. No spe cies within the SMG was capable of producing either glycosyltransferas e. No species within the SSG or SMG was able to produce dextranase act ivity. The ability of species to produce different types of enzymes wa s related to their taxonomy, allowing the differentiation of several n ew taxonomic types within the SSG and may be related to pathogenesis.