Reduced pyridine nucleotides balance in glucose growing Saccharomyces cerevisiae

Abstract

The quantitative importance of transhydrogenation from NADH to NADP in Saccharomyces cerevisiae growing on glucose has been investigated. To this aim, the contribution of the different metabolic pathways to glucose metabolism has been measured and a balance between the requirements and the production of reduced pyridine nucleotides has been established. The results suggest that the oxidative hexose monophosphate pathway accounts for all, or almost all, the cellular requirements for NADPH and that the reoxidation of NADH is effected for a part by the respiratory chain but mainly by enzymatic reactions coupled to the reduction of organic compounds like acetaldehyde or dihydroxyacetone phosphate. A significant transhydrogenation between pyridine nucleotides is therefore not likely to occur in S. cerevisiae growing on glucose.