Mucin-sulphatase activity of some oral streptococci.

Mucin-sulphatase activity, measured using a 35S-[SO4(2-)]-labelled colonic mucin substrate, was detected in whole cells of Streptococci isolated from the human oral cavity. The highest levels of sulphatase activity were found in all strains of Streptococcus salivarius, Streptococcus mitis and in half of the strains of Streptococcus mutans tested. Little or no activity was detected in 9 of the 11 Streptococcus oralis strains examined, in the 4 Streptococcus constellatus strains, and in the 3 Streptococcus anginosus isolates tested. The highest enzyme levels were obtained from the two fresh Streptococcus gordonii isolates. This is the first report of such activity in oral microorganisms. Streptococcal mucin-sulphatase may contribute to the destruction of salivary mucins and mitigate their protective functions in the oral cavity, and be a determinant in the development of dental caries.