锌(Ⅱ)存在下灯盏花素与BSA相互作用的光谱分析

运用荧光光谱、吸收光谱研究了灯盏花素(Breviscapinun,BR)与牛血清白蛋白(Bovine Serum Albumin,BSA)的相互作用.BR对BSA的荧光光谱具有猝灭作用,其猝灭机制为静态-动态联合猝灭,BSA发射峰蓝移.Zn2+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.在较大浓度Zn2+存在下,BR与BSA作用的相关系数增大,猝灭机制变为静态猝灭.从Zn2+与BR的竞争作用,热力学参数的变化、配位化合物的形成3个方面分析了影响BR与BSA作用的因素.     

荧光法研究金属离子对橙皮素与牛血清白蛋白相互作用的影响

采用荧光光谱和三维荧光光谱法研究了橙皮素(HSP)与牛血清白蛋白(BSA)之间的相互作用,并考察了共存金属离子Cu2+,Zn2+对二者相互作用的影响。实验结果表明,HSP对BSA的内源性荧光具有猝灭作用,猝灭类型为静态猝灭,作用力类型是氢键和范德华力,Cu2+,Zn2+的加入未改变HSP对BSA的猝灭类型和作用力类型。通过比较猝灭常数、结合常数、结合位点数、猝灭效率和三维荧光光谱图变化,推知Cu2+,Zn2+能与BSA产生结合作用,使其成为受制状态下的刚性肽链,从而影响HSP进入BSA疏水腔,减弱了HSP与BSA的结合能力,表现为与HSP存在竞争作用。     

维生素B1与牛血清白蛋白的相互作用

采用荧光猝灭光谱、同步荧光光谱研究了维生素B1与牛血清白蛋白(bovine serum albumin,BSA)的相互作用机制.维生素B1对BSA 有较强的荧光猝灭作用,结合Stern-Volmer方程和热力学方程得到结合常数和对应温度下的热力学参数,并结合紫外吸收光谱进一步验证,维生素B1对BSA的猝灭过程为动态猝灭,二者主要以氢键和范德华力结合.并采用同步荧光光谱探讨了维生素B1对BSA 构象的影响.此外,讨论了共存Ca2+、Cu2+、Al3+、Mg2+ 和K+ 对维生素B1与BSA结合作用的影响.     

锌离子对缓冲液中槲皮素和牛血清白蛋白相互作用的影响

采用荧光光谱法和紫外光谱法研究了Zn2+离子对槲皮素(Qct)和牛血清白蛋白(BSA)在pH=7.4的Tris-HCl缓冲溶液中相互作用的影响;根据荧光猝灭双倒数图计算了Qct和BSA之间的结合常数和结合位点数.结果表明,Qct和Zn2+离子都可以使BSA的荧光强度发生猝灭;Qct和BSA之间的结合常数为3.17×107L.mol-1.s-1,结合位点数为1.32.定量计算表明,加入Zn2+离子后,Qct与BSA间的结合常数显著降低、结合位点数减小,表明Zn2+离子参与了Qct与BSA的结合过程.     

铜、锌离子对齐墩果酸与蛋白质相互作用的影响

使用荧光光谱和紫外吸收光谱研究金属离子存在下对齐墩果酸(OA)与牛血清白蛋白(BSA)相互作用的影响.实验结果表明,生理pH值条件下齐墩果酸对牛血清白蛋白的荧光猝灭可能是一个单一的静态猝灭过程.求得了OA与BSA相互作用的结合常数为6.16×103 L·mol-1.Zn2+或Gu2+存在下,OA对BSA的荧光猝灭类型没...     

金属离子对叶酸与牛血清白蛋白相互作用的影响

用荧光光度法及紫外分光光度法研究了生理条件下金属离子Ca2+、Cu2+和Zn2+对叶酸(FA)与牛血清白蛋白(BSA)相互作用的影响。结果表明:叶酸及金属离子均导致BSA的内源荧光猝灭,根据Stern-Volmer方程得到的荧光猝灭常数,可判断猝灭机制均为静态猝灭。由计算得到的热力学参数熵变ΔS和Gibbs自由能ΔG得出:推断无金属离子存在时,FA与BSA之间的作用力为静电作用力;在Ca2+的存在下,FA对BSA的作用力主要为氢键与范德华力;Cu2+和Zn2+存在下,FA对BSA的作用力主要为疏水作用力。3种金属离子的参与都使得FA与BSA结合作用的表观结合常数发生了的变化,但结合位点数仍维持在1左右。     

Eu3+存在下盐酸头孢替安与牛血清白蛋白相互作用的研究

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.     

荧光光谱法研究培氟沙星与牛血清白蛋白结合反应特征

在不同温度下,扫描了培氟沙星(PEFL)与牛血清白蛋白(BSA)作用的荧光猝灭光谱、同步荧光光谱、三维荧光光谱和紫外可见吸收光谱,分别用Stern-Volm er方程、L ineweaver-Burk方程和热力学方程等处理实验数据,得到了结合反应的相关参数KLB、ΔHθ、ΔGθ和ΔSθ等的平均值分别为8.419×103L.mol-1、150.7 kJ.mol-1、-22.88 kJ.mol-1和561.9 J.K-1,结合位点数为1.081;证实了在实验浓度和温度范围内,PEFL与BSA可结合形成具有一定结构的复合物,荧光猝灭作用符合静态猝灭作用特征,作用力主要是疏水作用力和静电作用力;为研究PEFL的药理作用和生物学效应,以及PEFL对蛋白质构像的影响等提供了重要信息。     

Cr(Ⅵ)与牛血清白蛋白的相互作用

采用荧光光谱、紫外光谱、CD光谱法研究了K2Cr2O7与牛血清白蛋白(BSA)的相互作用。实验结果表明,铬(Ⅵ)使BSA的紫外吸收降低,峰位红移,表明铬(Ⅵ)与BSA发生较强的相互作用;铬(Ⅵ)酸根离子与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。测定了不同温度下该反应的热力学参数,ΔGθ0,ΔHθ和ΔSθ分别为-12.60kJ/mol和56.60J/(mol.k),表明上述作用过程是一个熵增加、自由能降低的自发分子间作用过程,铬(Ⅵ)酸根离子与BSA之间以静电作用力为主;非辐射能量转移机理确定了铬(Ⅵ)与牛血清白蛋白中色氨酸残基之间的距离r=2.85nm;同步荧光和CD光谱研究表明,铬(Ⅵ)使BSA的二级结构发生改变,α-螺旋含量降低,色氨酸残基所处微环境的极性减小。     

溴百里酚蓝与牛血清白蛋白的相互作用研究

在模拟动物体生理条件和不同温度下,用荧光光谱和紫外-可见吸收光谱法研究了溴百里酚蓝(BTB)与牛血清白蛋白(BSA)结合反应的光谱行为。用Stern-Volmer和Lineweaver-Burk方程分别处理试验数据,发现BSA与BTB发生反应生成了新的复合物,属于静态荧光猝灭。求出了反应时复合物的形成常数KLB(2.792×105L.mol-1)、热力学参数(ΔHθ=(20.24 kJ.mol-1,ΔSθ=37.22J.K-1,ΔGθ=(31.25kJ.mol-1)与结合位点数(1.1578)。根据F rster偶极-偶极非辐射能量转移理论计算出结合位置距离212位色氨酸残基2.60nm,证明二者主要靠静电作用力结合。同时用同步荧光光谱和三维荧光光谱法探讨了BTB对BSA构象的影响,表明BTB使色氨酸残基所处微环境的极性减弱、疏水作用增强,为阐明BTB的染色机理、毒理效应和生物学效应提供重要信息。     

Study on the interaction between salvianic acid A sodium and bovine serum albumin by spectroscopic methods

The interaction between salvianic acid A sodium (SAS) and bovine serum albumin (BSA) was investigated using fluorescence and ultraviolet spectroscopy at different temperatures under imitated physiological conditions. The experimental results showed that the fluorescence of BSA was quenched by SAS through a static quenching procedure. The binding constants of SAS with BSA were 2.03, 1.17 and 0.71×10(5) L mol(-1) at 291, 298 and 305 K, respectively. Negative values of ΔG, ΔH, and ΔS indicate that the interaction between SAS and BSA is driven by hydrogen bonds and van der Waals forces. According to F?rster non-radiation energy transfer theory, the binding distance between BSA and SAS was calculated to be about 2.92 nm. The effect of SAS on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy. In addition, the effect of some metal ions Cu(2+), Ca(2+), Mg(2+), and Zn(2+) on the binding constant between SAS and BSA was examined.     

变色酸与牛血清白蛋白的相互作用

采用荧光光谱法和紫外-可见分光光度法研究了变色酸与牛血清白蛋白之间的相互作用。结果表明:变色酸对牛血清白蛋白有较强的荧光猝灭作用。根据Stern-Volmer方程得到了荧光猝灭常数,并判断由于与变色酸反应而导致牛血清白蛋白的荧光猝灭属于静态猝灭。采用Lang-muir单分子吸附模型计算了结合常数和结合位点数。从计算得到的热力学参数ΔH和ΔS推断了变色酸与血清白蛋白反应的作用力为氢键和范德华力。     

Study on the Interaction of Raloxifene and Bovine Serum Albumin by the Tachiya Model

The interaction of bovine serum albumin (BSA) with raloxifene was assessed via fluorescence spectroscopy. The number of binding sites and the apparent binding constants between raloxifene and BSA were analyzed using the Tachiya model and Stern-Volmer equation, respectively. The apparent binding constant and the number of binding sites at 298 K were 2.33×10⁵ L?mol^?1 and 1.0688 as obtained from the Stern-Volmer equation and 2.00×10⁵ L?mol^?1 and 2.6667 from the Tachiya model. The thermodynamic parameters ΔH and ΔS were calculated to be 69.46 kJ?mol^?1 and 121.12 J?K^?1?mol^?1, respectively, suggesting that the force acting between raloxifene and BSA was mainly a hydrophobic interaction. The binding distance between the donor (BSA) and acceptor (raloxifene) was 4.77 nm according to Förster’s nonradiational energy transfer theory. It was also found that common metal ions such as K⁺, Cu²⁺, Zn²⁺, Mg²⁺ and Ca²⁺ decreased the apparent association constant and the number of binding sites between raloxifene and BSA.     

白杨素磺酸盐与牛血清白蛋白的相互作用

合成了白杨素磺酸钠和白杨素磺酸钙两种白杨素磺酸盐衍生物,并分别采用荧光光谱法研究了它们与牛血清白蛋白(BSA)的相互作用。结果表明:两种白杨素磺酸盐对BSA有较强的荧光猝灭作用,根据Stern-Volmer方程得到的荧光猝灭常数,可判断由于与白杨素磺酸盐反应而导致BSA的荧光猝灭均属于静态猝灭。采用位点结合模型公式和Frster非辐射能量转移理论计算了结合常数、结合位点数、结合距离。从计算得到的热力学参数焓变ΔH和熵变ΔS,推断了白杨素磺酸钠与BSA之间的作用力为静电引力,而白杨素磺酸钙与BSA之间的作用力为氢键和范德华力。并应用同步荧光技术研究了白杨素磺酸盐对BSA构象的影响。     

Study of the interaction between 2,5-di-[2-(4-hydroxy-phenyl)ethylene]-terephthalonitril and bovine serum albumin by fluorescence spectroscopy

A new compound, 2,5-di-[2-(4-hydroxy-phenyl)ethylene]-terephthalonitrile (DHPEPN), was synthesized. The interaction between bovine serum albumin (BSA) and DHPEPN in Tris-HCl buffer solution (pH 7.4) was investigated using fluorescence and UV-vis absorption spectroscopy. The mechanism of BSA fluorescence quenched by DHPEPN is discussed according to the Stern-Volmer equation. The binding constant and the thermodynamic parameters ΔH, ΔS, ΔG at different temperatures were calculated. The results indicate that the van der Waals interaction and hydrogen bonding play major roles in the binding process. The distance between BSA and DHPEPN is estimated to be 3.59 nm based on the F?rster resonance energy transfer theory. The spectral changes of synchronous fluorescence and three-dimensional fluorescence suggest that both of the microenvironment of DHPEPN and the conformation of BSA are changed during binding between DHPEPN and BSA.     

Fe3+存在下磺胺甲恶唑与牛血清白蛋白相互作用的光谱学研究

在模拟生理条件下,应用荧光光谱、紫外吸收光谱以及傅立叶变换红外光谱研究Fe3+存在下磺胺甲恶唑(Sulfamethoxazole,SMZ)与牛血清白蛋(Bovine Serum Albumin,BSA)的相互作用.结果表明,Fe3+存在时SMZ与BSA结合常数增大,作用力类型由疏水作用力转变为氢键和范德华力.无论Fe3...     

Study of the interaction between N-confused porphyrin and bovine serum albumin by fluorescence spectroscopy

The fluorescence and ultraviolet spectroscopy were explored to study the interaction between N-confused porphyrins (NCP) and bovine serum albumin (BSA) under imitated physiological condition. The experimental results indicated that the fluorescence quenching mechanism between BSA and NCP was static quenching procedure at low NCP concentration at 293 and 305 K or a combined quenching (static and dynamic) procedure at higher NCP concentration at 305 K. The binding constants, binding sites and the corresponding thermodynamic parameters ΔH, ΔS, and ΔG were calculated at different temperatures. The comparison of binding potency of the three NCP to BSA showed that the substituting groups in benzene ring could enhance the binding affinity. From the thermodynamic parameters, we concluded that the action force was mainly hydrophobic interaction. The binding distances between NCP and BSA were calculated using F?rster non-radiation energy transfer theory. In addition, the effect of NCP on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy.     

光谱法与分子模拟研究胡椒碱对牛血清白蛋白的键和作用

利用荧光光谱法及紫外吸收光谱法结合计算机模拟技术研究了在模拟生理条件下胡椒碱(piperine)与牛血清白蛋白(Bovine Serum Albumin, BSA)的相互作用. 根据荧光猝灭的有关方程分别求得不同温度下(298, 308和318 K)药物与蛋白相互作用的结合常数、结合位点数及键合距离. 实验所得到的热力学参数(ΔHӨ＝－9.55 kJ/mol, ΔSӨ＝46.75 J•mol－1•K－1)表明维持药物与蛋白质的相互作用力主要是疏水作用和静电作用. 分子模拟的结果显示了胡椒碱与BSA的键合机理和键合模式, 表明维持药物与蛋白质的相互作用力主要是疏水作用和氢键(位于氨基酸残基His 242, Arg 222和Arg 218位). 此外, 基于胡椒碱的荧光猝灭效应, 首次探讨了药物-蛋白质体系的几种物理化学参数, 包括电荷密度(δ)、离解常数(Kd)及量子产率(F)的变化效应.