Abstract
Disruption of the gene pgi1 of Saccharomyces cerevisiae, which codes for phosphoglucose isomerase, results in a dramatic increase in the amount of intracellular glycogen in early exponential cultures. The level or glucose 6-phosphate was much higher in mutant than in wild-type cells. Phosphorylase a activity and the state of activation of glycogen synthase were also investigated. Phosphorylase a activity was rather low along the culture in wild-type cells, whereas it was consistently higher in mutants. Glycogen synthase was mostly in the active form in early-medium exponential cultures in wild-type cells whereas the activation state of this enzyme in mutant cells, although lower at the earlier steps of the culture, did not differ from wild-type cells at later stages. The fact that the intracellular levels of UDP-glucose are markedly increased in mutant cells suggest that the observed accumulation of glycogen results from a rise in substrate availability rather than from the activation of the enzyme responsible for the synthesis of the polysaccharide. © 1992.
Original language | English |
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Pages (from-to) | 182-186 |
Journal | FEBS Letters |
Volume | 310 |
Issue number | 2 |
DOIs | |
Publication status | Published - 28 Sep 1992 |
Keywords
- Gene disruption
- Glycogen accumulation
- Glycogen synthase
- Phosphoglucose isomerase mutant
- Phosphorylase
- Saccharomyces cerevisiae