Glucose Induced Inactivation of Malate Dehydrogenase in Intact Yeast Cells

Abstract

The glucose‐dependent inactivation of malate dehydrogenase ( l ‐malate: NAD oxidoreductase, EC 1.1.1.37) in acetate‐grown yeast cells was studied in vivo. Among different yeast species inactivation was observed only in strains of the genus Saccharomyces. The phenomenon is initiated by the addition of glucose or related hexoses to the medium and is reversibly interrupted at 0°. By use of a yeast mutant requiring tryptophan, it was shown that malate dehydrogenase inactivation is not influenced by inhibition of protein synthesis, whereas recovery of enzyme activity in inactivated cells requires the presence of an energy source and tryptophan and is presumably due to de novo protein synthesis. The reported results provide evidence that a metabolite formed in the first steps of glycolysis might be responsible for initiation of malate dehydrogenase inactivation.