Effects of a hexokinase II deletion on the dynamics of glycolysis in continuous cultures of Saccharomyces cerevisiae

Abstract In glucose-limited aerobic chemostat cultures of a wild-type Saccharomyces cerevisiae and a derived hxk2 null strain, metabolic fluxes were identical. However, the concentrations of intracellular metabolites, especially fructose 1,6-bisphosphate, and hexose-phosphorylating activities differ...

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Bibliographic Details
Published in:FEMS yeast research 2002-05, Vol.2 (2), p.165-172
Main Authors: Diderich, Jasper A., Raamsdonk, Léonie M., Kuiper, Arthur, Kruckeberg, Arthur L., Berden, Jan A., Teixeira de Mattos, M. Joost, van Dam, Karel
Format: Article
Language:English
Subjects:
Aerobiosis
Chemostat culture
Crabtree effect
Culture Media
Gene Deletion
Genes, Fungal
Glucose - metabolism
Glucose repression
Glycolysis
Hexokinase - deficiency
Hexokinase - genetics
Hexokinase - metabolism
Hexokinase II
Saccharomyces cerevisiae
Saccharomyces cerevisiae - enzymology
Saccharomyces cerevisiae - genetics
Saccharomyces cerevisiae - metabolism
Transition
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Summary:Abstract In glucose-limited aerobic chemostat cultures of a wild-type Saccharomyces cerevisiae and a derived hxk2 null strain, metabolic fluxes were identical. However, the concentrations of intracellular metabolites, especially fructose 1,6-bisphosphate, and hexose-phosphorylating activities differed. Interestingly, the hxk2 null strain showed a higher maximal growth rate and higher Crabtree threshold dilution rate, revealing a higher oxidative capacity for this strain. After a pulse of glucose, aerobic glucose-limited cultures of wild-type S. cerevisiae displayed an overshoot in the intracellular concentrations of glucose 6-phosphate, fructose 6-phosphate, and fructose 1,6-bisphosphate before a new steady state was established, in contrast to the hxk2 null strain which reached a new steady state without overshoot of these metabolites. At low dilution rates the overshoot of intracellular metabolites in the wild-type strain coincided with the immediate production of ethanol after the glucose pulse. In contrast, in the hxk2 null strain the production of ethanol started gradually. However, in spite of the initial differences in ethanol production and dynamic behaviour of the intracellular metabolites, the steady-state fluxes after transition from glucose limitation to glucose excess were not significantly different in the wild-type strain and the hxk2 null strain at any dilution rate.
ISSN:1567-1356
1567-1364
DOI:10.1111/j.1567-1364.2002.tb00081.x