钠对酿酒酵母转化酶活性的影响。
Effect of sodium on Saccharomyces cerevisiae invertase activity.
作者信息
Raheja G, Gill R K, Kumar S, Mahmood S, Mahmood A
机构信息
Department of Biochemistry, Panjab University, Chandigarh, India.
出版信息
Indian J Exp Biol. 1998 May;36(5):493-6.
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.
研究了钠离子对酵母转化酶活性的影响，并将其作为pH值的函数进行研究。在酸性pH值下，5-100 mM的钠离子没有影响，但随着pH值升高（6.8和8.0），100 mM的钠离子会抑制转化酶活性（38-44%）。动力学分析表明，钠离子对转化酶的抑制是非竞争性且可逆的。在存在20-100 mM钠离子的情况下，米氏常数（K(m)）保持不变（33.3 mM），而在此条件下最大反应速度（Vmax）降低了21-44%。抑制常数（Ki）约为85 mM。文中描述了由于钠离子在酶活性位点的相互作用而导致观察到的转化酶活性抑制的机制。
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