ALPHA-GLUCOSIDASES OF STREPTOCOCCUS PYOGENES AND DERIVED L FORM

Two α-gluclosidases, maltase and isomaltase, were detected and isolated from mid-logarithmic grown cells of Streptococcus pyogenes and from the derived stable l form. These enzymes were localized in the cytoplasm of each organism and were resolved by gel filtration. It was found that in the presence of α-methylglucoside, the induced synthesis of these α-glucosidases was significantly greater (from 1.5 times or more) in the l form than in the parental coccus. l-form whole cells were found to accumulate this inducer to levels more than twice as high and at a faster rate than did S. pyogenes. Induction also occurred when maltose replace α-methyl-glucoside as the inducer. Induction of maltase and isomaltase leveled off or decreased in the coccus but continued within the l form as the concentration of either inducer was increased. Growth of S. pyogenes in l-form medium in the presence of either inducer proved that continued and increased enzymatic induction withi the l form was not due to an osmotic effect. These induction and labeled α-methylglucoside-uptake studies together with the observation that induced α-glucosidase synthesis is markedly inhibited by coccal cell wall carbohydrates in the streptococcus but not in the l form suggest that an alteration in the regulatory mechanism of α-glucosidase synthesis has occurred upon conversion of S. pyogenes to the l form. The possibility of these results being related to an inability by the l form to form a rigid cell wall is discussed. © 1969.