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Enzyme concentration affects the allosteric behavior of yeast phosphofructokinase
Biochemical and Biophysical Research Communications
|September 16, 1985
Summary
Enzyme concentration significantly impacts yeast phosphofructokinase activity, reducing ATP inhibition at higher concentrations. This suggests enzyme concentration affects the allosteric behavior of this key glycolytic enzyme.
Area of Science:
- Biochemistry
- Enzymology
- Metabolic Regulation
Background:
- Yeast phosphofructokinase is a crucial enzyme in glycolysis.
- Allosteric regulation is vital for controlling metabolic pathways.
- The effect of enzyme concentration on enzyme kinetics is not fully understood.
Purpose of the Study:
- To investigate the influence of enzyme concentration on the kinetic properties of yeast phosphofructokinase.
- To determine if enzyme concentration affects ATP inhibition and substrate saturation.
- To explore the role of enzyme concentration in the allosteric behavior of yeast phosphofructokinase.
Main Methods:
- Kinetic studies of purified yeast phosphofructokinase at varying concentrations.
- Enzyme activity assays in permeabilized yeast cells (in situ).
- Use of polyethylene glycol to modulate local protein concentration.
Main Results:
- Higher enzyme concentrations (120 µg/ml) significantly reduced ATP inhibition compared to diluted enzyme.
- This effect was observed both in purified enzyme and in situ.
- Polyethylene glycol mimicked the effect of higher enzyme concentration by reducing ATP inhibition.
- Enzyme concentration did not significantly alter the fructose-6-phosphate saturation curve.
Conclusions:
- Enzyme concentration is a critical factor influencing the allosteric regulation of yeast phosphofructokinase.
- Higher enzyme concentrations decrease the sensitivity to ATP inhibition.
- These findings highlight the importance of considering enzyme concentration in biochemical studies and understanding metabolic control.
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