Regulation of Glycolytic Flux and Ethanol Production in Saccharomyces cerevisiae: Effects of Intracellular Adenine Nucleotide Concentrations on the In Vitro Activities of Hexokinase, Phosphofructokinase, Phosphoglycerate Kinase, and Pyruvate Kinase.
The progressive decline in the glycolytic activity of Saccharomyces cerevisiae during batch fermentation is accompanied by changes in adenine nucleotide pools. The relative activities of four glycolytic enzymes were examined in vitro in the presence of nucleotide concentrations equivalent to intracellular pools. Phosphofructokinase and pyruvate kinase were not inhibited. Phosphoglycerate kinase was inhibited by AMP but was judged unlikely to be of physiological consequence owing to enzyme abundance. Both isoenzymes of hexokinase were strongly inhibited by AMP. The degree of hexokinase inhibition was sufficient to account for the observed decline in glycolytic activity during batch fermentation.
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Departamento de Microbiología, Instituto de Ciencias Biomedicas, Universidade de São Paulo, São Paulo, Brazil, and Department of Microbiology and Cell Science, 1052 McCarty Hall, University of Florida, Gainesville, Florida 32611.
Dombek
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Ingram
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