2-位碲桥联环糊精的制备、表征及其谷胱甘肽过氧化物酶活性的研究

摘要

该文以三种母体环糊精(CD),即α-β-和γ-CD为修饰模板,将功能性基团有机碲引入到环糊精次面的2位羟基上,制备得到了三种具有谷胱甘肽过氧化物酶(GPX)活性的GPX模拟物.采用元素分析、红外光谱、核磁共振等手段对三种环糊精衍生物的结构进行了表征.运用GPX经典双酶体系法测定了三种环糊精衍生物的GPX活性,实验结果表明三者均具有很高的催化活性,其中2-位碲桥联γ-环糊精(2-Te-γ-CD)具有最高的GPX活性,其催化谷胱甘肽(GSH)还原过氧化氢(H2O2),叔丁基过氧化氢(t-BuOOH)和枯烯过氧化氢(CuOOH)的活力分别是传统“小分子硒酶”Ebselen的80.5,333.3和118.3倍.%On the basis of structural understanding for GPX,cyclodextrins was selected as the scaffolds of enzyme models,and catalytic sites Te was introduced by chemical modification. Three novel glutathione peroxidase ( GPx) mimics based on organotellurium cyclodextrin dimer were synthesized. Their structures were identified by IR,'HNMR and elemental analysis. The decomposition of a variety of structurally distinct hydroperoxides at the expense of glutathione( GSH) catalyzed by 2,2' -ditellurobis(2-deoxy-y-cyclo-dextrin) (2-Te--y-CD) ,and by the corresponding derivatives of β-cyclodextrin(β-CD) and a-cyclodextrin was examined. Hydroperoxides decomposing capacity of 2-Te-y-CD was determined to be 80. 5 ,109. 8,149. 6 U/u,mol,respectively,with hydrogen peroxide ( H202) ,tert-butyl hydroperoxide(t-BuOOH) and cumene hydroperoxide( CuOOH) .which was almost 80. 5 ,333. 3,118. 3-fold than that of Ebselen.