光谱法研究Zn^(2+)对枸杞超氧化物歧化酶活力和结构的影响  

The Activity and Structure of Superoxide Dismutase of Lycium in the Existence of Zn^(2+) with Spectroscopy

作　　者：王欣欣[1] 李艳[1] 安丽萍[1] 高焕园 曹青[1] 靳利娥[1] 

机构地区：[1]太原理工大学化学化工学院,山西太原030024

出　　处：《光谱学与光谱分析》2017年第5期1455-1459,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(51174144)资助

摘　　要：针对提取的天然抗氧性物质超氧化物歧化酶量少,稳定性差等问题,实验以枸杞为原料,采用硫酸铵盐析分级分离方法提取了枸杞超氧化物歧化酶(superoxide disutase of lycium,SOD-LY),紫外光谱法确定了其类型;考察了不同种类的锌盐ZnSO_4,ZnCl_2,Zn(CH_3COO)_2和Zn(NO_3)_2对SOD-LY活力的影响,选择出能显著提高其活力的锌盐。采用傅里叶变换红外光谱、紫外光谱、荧光光谱法研究了最佳锌盐同SODLY分子的作用方式。结果表明,提取的SOD-LY属于Cu/Zn-SOD类型。不同浓度锌盐的存在均可影响SOD-LY的活性。其中,Zn(NO_3)_2对SOD-LY活力影响最大;红外光谱表明,Zn(NO_3)_2使SOD-LY二级结构中β-片层、β-转角和β-反平行结构减少,α-螺旋和无规则卷曲结构增多。荧光光谱分析得出,Zn^(2+)与SODLY之间的相互作用力主要为静电引力,有利于稳定SOD-LY的活性中心,使得SOD-LY活力增强。Zn^(2+)与SOD-LY结合常数(KΛ)为1.666×103 L·mol^(-1),结合位点数(n)为1.238,结合距离(r0)为3.62nm,该研究为提高SOD的活力、稳定性及扩展其应用提供理论帮助。As an important natural antioxidant,superoxide dismutase has been widely applied in fields such as diseases treatment as well as food,cosmetics and agriculture industries.In view of the poor stability of extraction quantity of SOD,the extraction of superoxide disutase from Lycium（SOD-LY）was carried out by salting-out separation with different levels of ammonium sulphate and reprecipitation with acetone in sequence.Its type was determined with ultraviolet spectrometry.The influence of different types of zinc salts such as ZnSO4,ZnCl2,Zn（CH3COO）2,Zn（NO3）2on activity of SOD-LY was investigated.The zinc salt enhancing its activity effectively was selected.The mode of interaction between the zinc salt selected and SOD-LY was studied with Fourier transform infrared spectroscopy,ultraviolet spectrum and fluorescence spectrometry.The analysis of results of ultraviolet spectrometry had shown that the SOD-LY extracted in the experiments consisted the type of Cu/zinc-SOD.The activity of SOD-LY can be influenced by different concentration of zinc salts such as zinc nitrate,zinc acetate,zinc chloride,sulfuric acid zinc and ethylene glycol.Among the investigated zinc salts,the activity of SOD-LY can be enhanced through using Zn（NO3）2 greatly.The analysis of infrared spectroscopy demonstrated thatβ-sheet layer,β-corner andβ-antiparallel all decrease,however,α-helix and unordered curling increases for the secondary structure of SOD-LY in the presence of Zn（NO3）2,This may be due to the presence of weakly interacting complex between them.Analysis of fluorescence spectrometry indicated that the fluorescence intensity of SOD-LY decreased due to the addition of Zn（NO3）2 whose binding constant was 1.666×103 L·mol-1while the binding site number was 1.238 according to the double logarithmic regression curve analysis.The distance is 3.62 nm by overlapping coverage area of the UV absorption spectra of SOD-LY and the fluorescence emission spectra of Zn（NO3）2-SODLY.The main action existed between Zn2＋and

关 键 词：超氧化物歧化酶 枸杞 活力 作用方式 

分 类 号：O657.33[理学—分析化学]