Saccharomyces cerevisiae aldolase mutants

Abstract

Six mutants lacking the glycolytic enzyme fructose 1,6-biphosphate aldolase have been isolated in the yeast Saccharomyces cerevisiae by inositol starvation. The mutants grow on gluconeogenic substrates, such as glycerol or alcohol, and show growth inhibition by glucose and related sugars. The mutations are recessive, segregate as one gene in crosses, and fall in a single complementation group. All of the mutants synthesize an antigen cross-reacting to the antibody raised against yeast aldolase. The aldolase activity in various mutant alleles measured as fructose 1,6-biphosphate cleavage is between 1 to 2% and as condensation of triose phosphates to fructose 1,6-biphosphate is 2 to 5% that of the wild-type. The mutants accumulate fructose 1,6-biphosphate from glucose during glycolysis and dihydroxyacetone phosphate during gluconeogenesis. This suggests that the aldolase activity is absent in vivo.