The effect of aeration intensity on the biochemical composition of Baker's yeast: Activities of enzymes of the glycolytic and pentose phosphate pathways

Abstract

AbstractA series of baker's yeast continuous cultivations were made using different intensities of aeration. The experimental conditions were such as to eliminate the effects caused by high glucose concentrations in the medium on the formation of enzymes. The variation in activity of several enzymes was investigated and distinct changes were noted. The activities of hexokinase and alcohol dehydrogenase characterize the actual rate of glycolysis in yeast, the same being true, in part, for pyruvate decarboxylase. The activity of phosphofructokinase is nearly insensitive to the oxygen level at normal tensions. The activity of the cell to the phosphofructokinase can be limited in anaerobic conditions by its scarcity. The insensitivity of glucose‐6‐phosphate dehydrogenase to the oxygen tension together with its low activity suggests that this enzyme plays primarily a biosynthetic role and that the function of the pentose phosphate pathway as an energy‐producing route is negligible.