【摘要】 以β-环糊精为酶模型,合成了具有谷胱甘肽过氧化物酶(GPx)活性的抗氧化模拟物6A,6A′-环己胺基-6B,6B′-二硒桥联-β-环糊精(6-CySeCD).采用元素分析、红外光谱1、3CNMR和X光电子能谱进行了结构表征.该模拟物的稳态动力学表现出米氏动力学特征,其催化机制可能与天然酶遵循相同的乒乓机制,催化GSH还原H2O2的GPx活力为7.9U/μmol,比Ebselen(0.99 U/μmol)高7.9倍,比6-SeCD(4.2 U/μmol)高1.8倍,即环己胺定向引入增强了其活力.更多还原

【Abstract】 On the basis of structural understanding for GPx,supromolecular host molecules,were selected cyclodextrins,as the scaffolds of enzyme models,and introduce catalytic sites Se and cyclohexylamine near the Se sites by chemical modification.One system of GPx mimic:cyclodextrin-based GPx models,6A,6B-cyclohexylamine-6A′,6B′-selenium-bridged β-cyclodextrin(6-CySeCD)was obtained.The structure of the mimic was characterized by means of elemental analysis,IR and 13CMR and its selenium content and valence were determined by means of x-ray photoelectron spectra.Double reciorocal plots of the inititial velocity versus the concentration of substrates were a family of parallel lines,consistent with a Ping-Pang mechanism involving at least one covalent enzyme intermediate.The GPx activity of the mimic for reduction of H2O2 by glutathione is 7.9 U/μmol,which is 7.9 times of that of ebselen.The GPx activity of the mimic for reduction of H2O2 by glutathione is 1.8 times of that 6-SeCD(4.2 U/μmol).Detailed steady-state kinetic studies demonstrated that the 6-SeCD followed a ping-pong mechanism similar to the naturally occurring GPx.Cyclohexylamine near the Se sites by chemical modification rose the activity of the mimic.更多还原