Dissolution and uptake of tooth phosphate by preparations of intact Streptococcus mutans cells containing acid phosphatase

Abstract

The caries-conducive streptococcus K-1, suspended in buffer, pH 5.8, under non-fermenting conditions, caused the release of more phosphate from the enamel than did the buffer alone. When rat tooth crowns, labelled with 32P, were incubated with a suspension of non-fermenting streptococci in buffer, the uptake of 32P of tooth origin by the organisms was more in the presence of potassium than in the presence of sodium. A factor capable of releasing enamel phosphorus, was eluted from the non-fermenting bacteria with strong chloride solutions. The factor was active in the presence of potassium ions. The release of enamel phosphate occurred again after precipitation of the eluted factor with acetone and buffer, pH 6.2, and the redissolution of the precipitate in water. This preparation also showed acid phosphatase activity against p-nitrophenyl phosphate with a peak activity at about pH 5.8. Both the eluted and uneluted cells showed acid phosphatase activity against the above substrate with the peak value at a more acid pH than that of the eluted preparation. The eluted cells also showed alkaline phosphatase activity against p-nitrophenyl phosphate.