Multicomponent nature of the glucosyltransferase system of Streptococcus mutans

The glucosyltransferases of S mutans 6715 were resolved into two major fractions. One fraction synthesized water-soluble glucans and the other made water-insoluble glucans. Each fraction was found by polyacrylamide gel electrophoresis to be composed of several catalytically active species, apparently glycoprotein in nature. Treatment of the glucosyltransferases with dextranase in the absence of sucrose caused an interconversion of enzyme forms concomitant with a time-dependent loss of enzyme activity, but did not appear to remove significant amounts of the carbohydrate associated with the enzymes. Comparison of enzyme activity patterns on polyacrylamide gels of the five different S mutans serotypes further emphasizes the complexity of the glucosyltransferase system from this group of microorganisms.