Acrylamide gel electrophoretic studies of extracellular sucrose-metabolizing enzymes of Streptococcus mutans.

This study explored the use of acrylamide gel electrophoretic methods to determine the numbers and types of extracellular sucrose-metabolizing enzymes produced by particular strains of S mutans. Strains HS-6, SL-1, FA-1, and NCTC 10449 were cultured in a chemically defined medium and the extracellular proteins elaborated by the organisms were isolated and subjected to acrylamide gel electrophoresis. Patterns of protein components and sucrose-metabolizing enzymes were then delineated. Three types of sucrose-metabolizing enzymes were observed. One type was involved in the synthesis of polysaccharides that were insolubilized in the gels. Another type was involved in the synthesis of water-soluble polysaccharides. A third type was involved in the splitting of sucrose into reducing sugars without polysaccharide synthesis. Each pattern was distinctive with regard to the numbers, proportions, and types of enzyme components present and their migratory characteristics. From two to at least six components were observed amont the enzyme activity patterns per strain. Extracellular protein patterns showed from 12 to 20 components per strain. Comparative data on growth in the chemically defined medium and Todd-Hewitt broth were also presented. Better growth levels were obtained in all instances with the chemically defined medium over comparable periods of time.