Yeast Malate Dehydrogenase: Enzyme Inactivation in Catabolite Repression

Abstract

The apparent inactivation of malate dehydrogenase activity in yeast following exposure to glucose has been studied. It was found to be prevented by inhibition of protein synthesis with cycloheximide, by addition of sodium azide, and by chilling the yeast to 0°. Kinetic evidence suggests that malate dehydrogenase from acetate‐induced and glucose‐repressed yeast are different molecular species. Possible mechanisms for “inactivation‐repression” are discussed.