α-GLUCOSIDASE, α-GLUCOSIDE PERMEASE, MALTOSE FERMENTATION AND LEAVENING ABILITY OF BAKER'S YEAST

α-Glucosidase and α-glucoside permease are synthesized simultaneously in two different strains of baker's yeast (Saccharomyces cerevisiae) when the cells are induced with maltose. α-Thioethyl D-glucopyranoside (α-TEG) inhibits the transport of maltose into the cells, and the transport of maltose and α-TEG appeared to be mediated by the same permease system. There is an obvious correlation between α-glucosidase, α-glucoside permease and maltose fermentation activities in the yeasts while no correlation between these and the leavening ability of the yeasts can be demonstrated. Apparently the glucose concentration in dough is high enough to inhibit the permease-mediated transport of maltose into the cells thus impairing leavening ability from the maltose fermenting system.