Effect of sodium on Saccharomyces cerevisiae invertase activity.
Effect of Na+ ions on yeast invertase activity has been studied as a function of pH. At acidic pH, Na+ (5-100 mM) had no effect but invertase activity was inhibited (38-44%) by Na+ ions (100 mM) with an increase in pH (6.8 and 8.0). Kinetic analysis revealed that invertase inhibition by Na+ ions was non-competitive and reversible in nature. Value of K(m) remained unaltered (33.3 mM) in presence of Na+ (20-100 mM) while Vmax decreased by 21-44% under these conditions. Value of Ki was of the order of 85 mM. Mechanism of observed inhibition of invertase activity as a consequence of Na+ ions interactions at the active site of the enzyme has been described.
Department of Biochemistry, Panjab University, Chandigarh, India.
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Raheja
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Gill
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Kumar
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Mahmood
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Mahmood
D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors* / Q000276:immunology; D006863:Hydrogen-Ion Concentration; D007106:Immune Sera; D007700:Kinetics; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D012964:Sodium / Q000378:metabolism*; D043324:beta-Fructofuranosidase
D007106:Immune Sera; D012964:Sodium; D006026:Glycoside Hydrolases; D043324:beta-Fructofuranosidase