Effect of a nonmetabolizable analog of fructose-1,6-bisphosphate on glycolysis and ethanol production in strains ofSaccharomyces cerevisiae andEscherichia coli

Fructose-1,6-bisphosphate (F-1,6-P2) is an allosteric activator of two key enzymes of glycolysis: phosphofructokinase and pyruvate kinase. Regulation of glycolysis in a wild-typeSaccharomyces cerevisiae and a recombinantEscherichia coli by a dead-end structural analog of F-1,6-P2 was studied. 2,5-Anhydromannitol (2,5-AM), a structural analog of β-d-fructose, was used. On being taken up by the cells, 2,5-AM was converted into its monophosphate and diphosphate by the enzymes of the glycolytic pathway. The final product, 2,5-anhydromannitol-1,6-bisphosphate, could not be metabolized further and, therefore, accumulated inside the cells. Glucose and fructose were used as substrates. It was found that 2,5-AM at concentrations of 1 mM or less did not have any effect on either substrate consumption or ethanol production. At concentrations of 2,5-AM of 2.5 mM or greater, significant inhibition of both glucose and fructose was observed, with fructose inhibition much more severe. We discuss the possible mechanisms of glycolysis inhibition by 2,5-AM at high concentrations and the regulation of glycolysis by this compound.