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为了解过渡金属华法灵配合物的抗凝血机理,本文采用荧光光谱、紫外吸收光谱和圆二色谱法(CD)研究了具有抗凝血作用的华法灵过渡金属配合物与人血清白蛋白(HSA)的相互作用。观察到配合物能使人血清白蛋白荧光产生猝灭现象,猝灭方式为静态猝灭,并计算了配合物与人血清白蛋白的结合常数K(约106)和结合位点数n(>1)。根据不同温度下的热力学函数,确定了配合物与人血清白蛋白之间的作用力为氢键和范德华力。发现华法灵过渡金属配合物的存在改变人血清白蛋白的构象,并讨论了配合物使人血清白蛋白构象发生变化的可能原因。配合物的抗凝血作用与其通过改变HSA的构象,进而影响血清白蛋白在血液中的溶解性之间有一定的关系。 相似文献
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采用荧光光谱法,紫外光谱法以及圆二色谱法研究了具抗凝血作用的水杨酸钕((NdL′3.2H2O,L′=水杨酸离子))、华法灵钕(NdL3.2H2O,L=华法灵离子)和华法灵水杨酸钕(NdL2L′.2H2O)3种配合物与人血清白蛋白的相互作用。结果表明:配合物对人血清白蛋白(HSA)的荧光产生猝灭现象;配合物的存在使得HSA紫外吸收光谱的强度增加;配合物的存在也对HSA的构象产生影响。水杨酸钕的猝灭方式为动态与静态猝灭,而华法灵钕和华法灵水杨酸钕的猝灭方式属于两者之间生成了不发荧光的复合物而导致的静态猝灭。并分别确定了它们的结合力类型:华法灵钕与HSA之间主要作用力是静电作用力;水杨酸钕与HSA之间主要作用力为典型的疏水作用力;华法灵水杨酸钕与HSA之间为氢键和范德华力。计算了配合物与人血清白蛋白的结合常数K和结合位点数n。 相似文献
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骨螺紫及其铜配合物与人血清白蛋白相互作用的光谱学研究 总被引:2,自引:0,他引:2
采用荧光光谱法、紫外光谱法和傅里叶红外光谱法(FTIR)研究了模拟生理条件下人血清白蛋白(HSA)与骨螺紫(Mx)及其铜配合物(Mx-Cu2+)的相互作用. 根据荧光猝灭数据, 二元体系与三元体系中的作用机制均为静态猝灭, 在Cu2+存在下, HSA与Mx之间的结合常数与结合位点数明显加大, 结合两个体系的紫外吸收光谱可知, 在三元体系中, Cu2+与Mx形成配合物后再与HSA发生作用; 根据Förster能量转移理论, 求得Mx及Mx-Cu2+与HSA上氨基酸残基间的距离分别为r=2.82 nm和r=2.53 nm, 三元体系能量转移效率E′大于二元体系E, 说明Cu2+在结合作用中可能起到了能量转移介质的作用; 对Δλ=60 nm时的同步荧光光谱的分析表明, 在Mx及Mx-Cu2+作用下, HSA色氨酸残基的微区构象发生了变化, 色氨酸残基所处环境的极性增加; 运用FTIR技术定量测定了HSA与Mx及Mx-Cu2+作用后二级结构的变化, 发现2个体系中HSA二级结构变化情况基本一致, α-螺旋结构明显减少约8%, β-折叠也减少约1%, 而β-转角和无规卷曲分别增加了约6%和4%. 说明对HSA二级结构造成影响的主要因素是Mx, 它与HSA的结合使蛋白质分子中的肽链部分展开, 二级结构从α-螺旋和β-折叠向β-转角和无规卷曲结构转变, 分子结构的松散程度增加. 相似文献
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以光谱技术和微量热技术相结合的方法研究水溶液中氟罗沙星分子及铁存在时与人血清白蛋白之间结合作用的机制,用荧光淬灭法测得两反应的结合常数分别为K=1.19×l05L·mol-1和1.0565×105L·mol-1,结合位点数0.97和0.835.依据Fōrster非辐射能量转移机制,得到氟罗沙星与人血清白蛋白间的结合距离(r=3.23nm).用同步荧光技术考察氟罗沙星对人血清白蛋白构象的影响.微量热法测得氟罗沙星与人血清白蛋白反应的ΔH≈0,ΔS>0,氟罗沙星分子在铁离子存在时与人血清白蛋白反应的ΔH<0,并且ΔS>0表明它们的作用都主要为静电力.由于焓熵互补的作用,两反应的自由能没有发生大的变化. 相似文献
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Oseltamivir phosphate (OP; tamiflu) is an antiviral pro-drug, which is hydrolyzed hepatically to the active metabolite oseltamivir carboxylate (OC). It is the first orally neuraminidase inhibitor that was used in the treatment and prophylaxis of influenza virus A and B infection. Human serum albumin (HSA) is the most abundant of the proteins in the blood plasma and is major transporter for delivering several drugs in vivo. This study was designed to examine the interaction of HSA with oseltamivir phosphate (OP) and oseltamivir carboxylate (OC) in aqueous solution at physiological conditions, using a constant protein concentration and various drug contents. FTIR, UV-Vis spectroscopic methods were used to determine the drugs binding mode, the binding constant and the effects of drug complexation on protein secondary structure. Structural analysis showed that OP and OC bind HSA via polypeptide polar groups with overall binding constants of K(OP-HSA)=3.86(± 1.05)× 10(3)M(-1) and K(OC-HSA)=1.5(±0.45) × 10(2)M(-1). The alterations of protein secondary structure are attributed to a partial destabilization of HSA on drug complexation. The protein secondary structure showed no major alterations at low drugs concentrations (50 μM), whereas at higher content (1mM), decrease of α-helix from 58% (free HSA) to 38% (OP-HSA)-48% (OC-HSA), decrease of random coil from 15% (free HSA) to 2% (OP-HSA)-3% (OC-HSA), increase of β-sheet from 6% (free HSA) to 20% (OC-HSA)-29% (OP-HSA) and turn from 8% (free HSA) to 17% (OC-HSA)-19% (OP-HSA) occurred in the drug-HSA complexes. These observations indicated that low drug content induced protein stabilization, whereas at high drug concentration, a partial protein destabilization occurred in these drug-HSA complexes. 相似文献
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采用荧光和紫外-可见吸收光谱,研究了大豆苷元与牛血清白蛋白(BSA)的相互作用.结果表明大豆苷元对BSA有较强的荧光猝灭作用;根据Stern-Volmer方程得到大豆苷元与BSA之间的结合常数KA为0.385×105 (30℃)、0.405×105(40℃)和0.431×105(50℃).根据F(o)rster非辐射能量转移理论,求出了大豆苷元与BSA之间的结合距离为2.34 nm(30℃)、2.48 nm(40℃)和2.71 nm(50℃).热力学数据表明大豆苷元与BSA之间的作用力主要为疏水作用力,同时用同步荧光光谱探讨了大豆苷元对BSA构象的影响. 相似文献
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Cheng FQ Wang YP Li ZP Dong C 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(5):1144-1147
The binding of bromsulphalein (BSP) with human serum albumin was investigated at different temperatures, 298 and 308 K, by the fluorescence spectroscopy at pH 7.24. The binding constant was determined by Stern-Volmer equation based on the quenching of the fluorescence HSA in the presence of bromsulphalein. The effect of various metal ions on the binding constants of BSP with HSA was investigated. The thermodynamic parameters were calculated according to the dependence of enthalpy change on the temperature as follows: DeltaH and DeltaS possess small negative (9.3 kJ mol(-1)) and positive values (22.3 J K(-l)mol(-l)), respectively. The experimental results revealed that BSP has a strong ability to quench the intrinsic fluorescence of HSA through a static quenching procedure. The binding constants between BSP to HSA were remarkable and independent on temperature. The binding constants between HSA and BSP decreased in the presence of various ions, commonly decreased by 30-55%. The hydrophobic force played a major role in the interaction of BSP with HSA. All these experimental results and theoretical data clarified that BSP could bind to HSA and be effectively transported and eliminated in body, which could be a useful guideline for further drug design. 相似文献
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通过光谱法研究了三种磺化酞菁(α位四磺化酞菁、β位四磺化酞菁和α位单取代磺化酞菁)与人血清白蛋白(HSA)的相互作用.结果 表明,HSA对α位四磺化酞菁的存在状态(单体、聚集体)影响显著,而对β位四磺化酞菁和α位单取代磺化酞菁的存在状态没有明显影响.磺化酞菁与HSA均存在明显的相互作用,且.四磺化酞菁与HSA的结合作用... 相似文献
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用分子对接方法及紫外-可见吸收光谱、同步荧光光谱、三维荧光光谱等实验手段研究了噻螨酮(HEX)与人血清白蛋白(HSA)的相互作用及对HSA构象的影响.预测结果表明,HEX能与HSA发生相互作用,且作用位点site II比site I的打分小约4.5.实验结果表明,HEX猝灭HSA的内源荧光且作用机制为静态猝灭;HEX使HSA周围的微环境发生变化,导致蛋白质的肽链结构改变;298和291 K时HEX与HSA相互作用的结合常数(KA)和结合位点数分别为7.35×103 mol/L、0.82和1.02×104 mol/L、0.86,证实HEX仅在site II存在作用位点;HEX与Trp214的结合距离为3.01 nm,作用力主要为氢键、范德华力和疏水作用力.这些研究所获得的多种信息有助于在分子水平上理解农药对人体造成的毒性及可能的生物累积性. 相似文献
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This study examined the interaction of indirubin with bovine serum albumin (BSA) at three temperatures (286, 297, 308 K) at pH 7.40. In the presence of indirubin, the drug-BSA binding mode, binding constant and the protein structure changes in aqueous solution were determined by fluorescence quenching methods including Fourier transform infrared (FT-IR) spectroscopy and UV-Vis spectroscopy. The FT-IR change indicates that indirubin binds to BSA. The change in protein secondary structure accompanying ligand binding has been proved by fluorescence spectra data. The thermodynamic parameters, the enthalpy change (DeltaH), and the entropy change (DeltaS) calculated by the van't Hoff equation possess small negative (-2.744 kJ.mol(-1)) and positive values (112.756 J.mol(-1).K(-1)), respectively, which indicated that hydrophobic interactions play the main role in the binding of indirubin to BSA. Furthermore, the displacement experiment shows that indirubin can bind to the subdomain IIA and the distance between the tryptophan residues in BSA and indirubin bound to site I was estimated to be 2.24 nm according to F?ster's equation on the basis of fluorescence energy transfer. 相似文献