Cell-bound glucosyltransferase activity of Streptococcus sanguis strain 804

Abstract

Cell-bound glucosyltransferase (GT) activity of washed cells of Streptococcus sanguis, strain 804, represents about 12 per cent of the total GT activity of glucose-grown cultures of this organism. During culture, cell-associated GT activity could be detected prior to its being found extracellularly. Sonication of the washed cells harvested at the stationary phase indicated that predominant proportions of GT and β-fructofuranosidase (FH) activities were associated with the cell debris fraction. Extracellular fibrillar material, demonstrated by electron microscopic examination, was synthesized by washed cells incubated with sucrose and chemical analysis indicated glucan formation. Incubation with sucrose also promoted the osmotic diffusion of proteins from the intracellular phase. Sodium fluoride inhibited cell metabolism without effecting the formation of glucan or the release of proteins into the supernatant fluid. Maltose in equimolar concentration with sucrose considerably reduced the synthesis of insoluble glucans. Washed cells incubated with sucrose did not release any GT.