镍离子与酵母乙醇脱氢酶的相互作用(英文)

Interaction of Nickel(Ⅱ) with Yeast Alcohol Dehydrogenase

不同体系中, 金属离子与蛋白以不同的结合方式相互作用. 酵母乙醇脱氢酶是一个含锌金属酶, 它可催化乙醇脱氢为乙醛的反应. 本文应用紫外-可见光谱、荧光光谱、差示扫描量热法等技术研究了二价镍离子与酵母乙醇脱氢酶的相互作用. 镍离子与酶结合后在 320 nm 出现了紫外吸收带, 同时荧光光谱反映了酶的构象变化, 紫外与荧光光谱均展现了结合过程的双相动力学. 镍离子与酶的相互作用导致了酶由四聚体向二聚体的解离; 在酶热变性过程中, 镍离子增加了乙醇脱氢酶的变性温度和变性焓. 研究工作揭示了镍离子与酶相互作用复杂和深层的作用机制.

The binding mode of metal ions with proteins is usually different in different systems.Yeast alcohol dehydrogenase （YADH） is a zinc containing metalloenzyme that catalyzes the fermentation reaction of alcohol to acetaldehyde.UV-Vis spectroscopy,fluorescence spectroscopy,and differential scanning calorimetry （DSC） were used to investigate the interaction of nickel（Ⅱ） with Yeast alcohol dehydrogenase.The binding of Ni（Ⅱ） to Yeast alcohol dehydrogenase shows a 320 nm UV absorbance band and the enzyme conformational change is reflected in the fluorescence data.Both UV-Vis and fluorescence spectra exhibit biphasic kinetics for the binding process.The interaction of Ni（Ⅱ） with Yeast alcohol dehydrogenase causes the enzyme to transform from a tetramer to a dimer.The conformational change of the Yeast alcohol dehydrogenase results in an increase in the denaturation temperature and in a molar enthalpy change during the DSC process.This study reveals a complex but deep-seated mechanism for the interaction of Ni（Ⅱ） with YADH.