In Schizosaccharomyces pombe, inositol-deficiency caused a decrease in Crabtree effect and an enhanced Pasteur effect. A time-course estimation of intracellular glucose , glycolytic intermediates, ATP and other components showed that decreased glycolytic activity possibly occurred before low glucose uptake activity and that low transport activity could hardly have caused of low glycolytic activity. The activities of all glycolytic enzymes tested seemed to be low in vivo , as well as the activities of enzymes in the hexose mono-phosphate shunt. These results suggest that inositol deficiency caused pleiotropic situation, possibly due to structural abnormality. The possible cause of low aerobic fermentation activity may be due to the difference in Km values between pyruvate dehydrogenase complex and pyruvate decarboxylase. An oxidative phosphorylation-uncoupling mutant was isolated and was used in these investigations .