EDTA和金属离子对酵母蔗糖酶天然酶和修饰酶酶活力的影响及其作用机理研究

摘要

以不同浓度EDTA、Mn2＋．Zn2＋和Fe2＋为效应物，以蔗糖为底物，研究EDTA和金属离子对酵母蔗糖酶（Yeastinvertase）天然酶和修饰酶催化活性的影响。结果表明：EDTA对天然酶和修饰酶均有抑制作用。Mn2＋对天然酶和修饰酶有激活作用；Zn2＋和Fe2＋对天然酶有抑制作用．对修饰酶有激活作用。动力学分析显示，经5mmol／LEDTA、Mn2＋．Zn2＋和Fe2＋处理后，天然酶和修饰酶的Km和Vmax值均发生变化。光谱分析显示．经不同浓度EDTA和Fe2＋处理后，天然酶和修饰酶的构型构象发生变化；经不同浓度Mn2＋和Zn2＋处理后，天然酶和修饰酶的构型构象基本上没有发生变化。%EDTA and different metal ions were used as effectors,and sucrose as substrate in order to study the effects of EDTA and different metal ions on enzyme specific activity of yeast invertase and its modified enzyme.The metal ions included Mn2＋,Zn2＋ and Fe2＋.The results showed that the treatment of EDTA restrained the activity of natural enzyme and modified enzyme.Mn2＋ activated the activity of natural enzyme and its modified enzyme. Zn2＋ and Fe2＋ activated the activity of modified enzyme but restrained natural enzyme.Kinetic analysis showed that the value of Km and Vmax changed after the treatment of 5 mmol/L EDTA and different metal ions.The spectral analysis showed that the configuration and conformation of natural enzyme and modified enzyme were changed after the treatment of EDTA and Fe2＋.However, after the treatment of Mn2. and Zn2＋,the configuration and conformation of natural enzyme and modified enzyme did not change.