共查询到19条相似文献,搜索用时 575 毫秒
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应用光谱方法研究了生理条件下(pH=7.40)拉米夫定与牛血清白蛋白(BSA)的相互作用.结果表明,拉米夫定对BSA产生强烈猝灭作用,其荧光猝灭过程属于静态猝灭.在295K和299 K时,拉米夫定与BSA结合常数分别为1.80x104和1.17x105L?mol-1.BSA的结合力是疏水作用力.探讨了拉米夫定对BSA构... 相似文献
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金属离子对次野鸢尾黄素与牛血清白蛋白相互作用的影响 总被引:2,自引:1,他引:1
应用荧光光度法研究了金属离子Fe3 、Ca2 、Cu2 或Mn2 对次野鸢尾黄素(IFR)与牛血清白蛋白(BSA)相互作用的影响.实验结果表明,不存在金属离子时,IFR对BSA的荧光猝灭过程为动态猝灭,其结合过程的表观结合常数KA值为104~105数量级,结合位点数n约等于1.由热力学参数得出IFR与BSA结合过程是一个熵增加、Gibbs自由能降低的自发过程,分子间相互作用力以疏水作用力为主.在Fe3 或Ca2 抖的存在下,IFR对BSA的荧光猝灭类型由动态猝灭转变为静态猝灭,作用力类型也由以疏水作用力为主转变为以氢键与范德华力为主或以静电引力为主.Cu2 或Mn3 存在下,IFR对BSA的荧光猝灭类型及分子间作用力类型均没有发生改变.四种金属离子的参与都使得IFR与BSA结合作用的袁观结合常数发生了明显的变化,但结合位点数仍维持在1左右. 相似文献
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Arteannuin (1), a new sesquiterpene lactone containing a peroxide group, is the antimalarial active principle isolated from Artemisia annua L. Deoxyarteannuin (2) occurs in the same plant and was isolated as a metabolite from the urine of patients treated with arteannuin. We now report a stereocontrolled synthesis of these two naturally occurring sesquiterpene lactones starting from arteannuic acid (5) by the reaction sequence as shown in Scheme 2 (see Chinese Text). Irradiation of the methanolic solution of the key intermediate 3 in the resence of oxygen and a sensitizer (Rose Bangal) with 200 W high pressure mercury lamp followed by acid treatment gave 1 in 28% yield (2 steps), m.p. 151-153`c, 相似文献
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金属离子对齐多夫定与牛血清白蛋白结合作用的影响 总被引:5,自引:0,他引:5
用荧光光谱法和紫外分光光度法研究了水溶液(Tris-HCl缓冲溶液, pH 7.1)中齐多夫定(ZDV)与牛血清白蛋白(BSA)的结合作用及三种金属离子(Cu2+, Mg2+, Zn2+)对其的影响. 结果表明: 齐多夫定及金属离子均导致BSA的内源荧光猝灭, 猝灭机制均为静态猝灭; 齐多夫定与BSA间存在较强结合作用, 热力学参数△H和△S分别为-10.2 kJ·mol-1和77.5 J·mol-1·K-1 (298 K), 表明其结合力以静电作用力为主; 298 K下结合常数、结合位点数和结合距离分别为6.92×105 L·mol-1、1.18和2.28 nm; 温度升高结合常数和结合位点数减小. 三种金属离子均导致ZDV与BSA的结合常数减小, 结合距离增大. 相似文献
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The interaction between cinnamic acid and bovine serum albumin (BSA) have been studied at three temperatures, 296, 303 and 310 K. Fluorescence quenching spectra in combination with Fourier transform infrared (FT-IR) spectroscopy and circular dichroism (CD) spectroscopy was used to investigate the drug-binding mode, the binding constant and the protein structure changes in the presence of cinnamic acid in aqueous solution at pH 7.40. The fluorescence quenching constant K(q), K(sv) and the binding constant K were calculated according to Stern-Volmer equation based on the quenching of the fluorescence of BSA in the presence of cinnamic acid. The thermodynamic parameters, the enthalpy (DeltaH) and the entropy change (DeltaS) were estimated to be -16.457 kJ mol(-1) and 38.028 J mol(-1) K(-1) according to the van't Hoff equation. The displacement experiment shows that cinnamic acid can bind to the subdomain IIA (corresponding to Sudlow's drug binding site I). The distance between the tryptophan residues in BSA and cinnamic acid bound to site I was estimated to be 1.63 nm using F?ster's equation on the basis of fluorescence energy transfer. The decreased binding constant in the presence of common ions indicates that common ions have effect on drug-BSA system. 相似文献
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运用荧光光谱、紫外吸收光谱研究了Eu3+存在下盐酸头孢替安(Cefotiam Hydro-chloride,CH)与牛血清白蛋白(BSA)的相互作用.CH对BSA具有荧光猝灭作用,其猝灭机制为静态猝灭,BSA发射峰蓝移,二者之间的作用力主要为疏水作用和弱的静电作用.Eu3+的存在使得BSA发射峰蓝移程度降低,猝灭常数、结合常数、结合位点数减小,但没有改变CH对BSA的猝灭机制,热力学参数ΔH和ΔS都增大.从热力学参数的变化及Eu3+的竞争作用分析了Eu3+对CH与BSA作用影响的原因. 相似文献
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三种香豆素类中药小分子与牛血清白蛋白的相互作用 总被引:36,自引:2,他引:34
运用荧光光谱(FS)、紫外光谱(UV)法研究了三种香豆素中药小分子与牛血清白蛋白(BSA)的相互作用.实验结果表明,香豆素类小分子能够插入BSA分子内部与BSA形成基态复合物导致BSA内源荧光猝灭,猝灭机理主要为静态猝灭和非辐射能量转移.药物分子极性及体积增大对BSA内源性荧光猝灭效应增强,与BSA中荧光性氨基酸残基之间的空间距离r增大,表观结合常数KA增大且结合位点数n减少.结合过程的热力学参数变化表明上述相互作用过程是一个熵增加、Gibbs自由能降低的自发分子间作用过程,其中香豆素与BSA之间以疏水作用为主,而伞形花内酯、七叶内酯与BSA之间则还存在偶极-偶极作用,表明药物分子极性同样影响其与BSA间相互作用力的类型. 相似文献