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.     

The investigation of the interaction between NCP-EDA and bovine serum albumin by spectroscopic approaches

The fluorescence and ultraviolet spectroscopies were explored to study the interaction between N-confused porphyrins-edaravone diad (NCP-EDA) and bovine serum albumin (BSA) under simulative physiological condition at different temperatures. The experimental results show that the fluorescence quenching mechanism between NCP-EDA and BSA is a combined quenching (dynamic and static quenching). The binding constants, binding sites and the corresponding thermodynamic parameters (ΔG, ΔH, and ΔS) of the interaction system were calculated at different temperatures. According to F?rster non-radiation energy transfer theory, the binding distance between NCP-EDA and BSA was calculated to be 3.63 nm. In addition, the effect of NCP-EDA on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy.     

Analysis of binding interaction between pegylated puerarin and bovine serum albumin by spectroscopic methods and dynamic light scattering

The interaction between bovine serum albumin (BSA) and pegylated puerarin (Pur) in aqueous solution was investigated by UV-Vis spectroscopy, fluorescence spectroscopy and circular dichroism spectra (CD), as well as dynamic light scattering (DLS). The fluorescence of BSA was strongly quenched by the binding of pegylated Pur to BSA. The binding constants and the number of binding sites of mPEG(5000)-Pur with BSA were 2.67±0.12 and 1.37±0.05 folds larger after pegylating, which were calculated from the data obtained from fluorescence quenching experiments. The enthalpy change (ΔH) and entropy change (ΔS) were calculated to be 4.09 kJ mol(-1) and 20.01 J mol(-1) K(-1), respectively, according to Van't Hoff equation, indicating that the hydrophobic force plays a main role in the binding interaction between pegylated Pur and BSA. In addition, the negative sign for Gibbs free energy change (ΔG) implies that the interaction process is spontaneous. Moreover, the results of synchronous fluorescence and CD spectra demonstrated that the microenvironment and the secondary conformation of BSA were changed. Comparing with Pur, all our data collected indicated that pegylated Pur interacted with BSA in the same way as that of Pur, but docked into the hydrophobic pocket of BSA with more accessibility and stronger binding force. DLS measurements showed monomethoxy polyethylene glycol (mPEG) have an effect on BSA conformation, and revealed that changes in BSA size might be due to increases in binding constant and the absolute values of ΔG after Pur pegylation.     

荧光光谱法研究橙皮苷与牛血清白蛋白相互作用特征

研究了不同温度下,橙皮苷与牛血清白蛋白作用的荧光猝灭光谱、三维荧光光谱和同步荧光光谱特征。证实了橙皮苷与牛血清白蛋白间的相互作用为单一的动态猝灭过程,求出了不同温度下的猝灭常数。根据Frster非辐射能量转移理论,计算出橙皮苷在蛋白质中的结合位置与212位色氨酸残基间的距离为3.29 nm。由求得的热力学参数,证明了橙皮苷与牛血清白蛋白之间主要靠疏水作用力结合。用三维荧光光谱及同步荧光光谱技术探讨了橙皮苷对牛血清白蛋白构象的影响。     

胡椒酸与牛血清白蛋白相互作用的研究

用荧光光谱及紫外光谱法模拟研究生理条件下胡椒酸与牛血清白蛋白(BSA)的相互作用。结果表明,胡椒酸与BSA形成基态复合物从而猝灭BSA的内源性荧光,猝灭原因主要为静态猝灭和非辐射能量转移。胡椒酸对BSA的猝灭速率常数Kq为2.969×1013(18℃)、2.491×1013(25℃)和2.328×1013L·mol-1·s-1(37℃)。胡椒酸与BSA的结合常数KA为1.01×105(18℃)、2.06×104(25℃)和1.02×104L·mol-1(37℃),结合位点数n为0.90(18℃)、0.77(25℃)和0.72(37℃)。根据Frster偶极-偶极非辐射能量转移理论得到结合距离r为2.47(18℃)、2.52(25℃)和2.54(37℃)nm。确定胡椒酸与BSA有较强的相互作用,可以被蛋白质所储存和运输。     

丝裂霉素C与牛血清蛋白结合作用的研究

结合光谱法与微量热法研究了水溶液中丝裂霉素C与牛血清白蛋白分子间的结合反应,测定了反应的结合常数K~A,结合位点数n及热力学函数△~rG~m,△~rH~m和△~rS~m,并确定了分子间作用力性质;依据Forster非辐射能量转移机制,确定了授体-受体间的结合距离和能量转移效率;采用同步荧光技术考察了丝裂霉素C对牛血清白蛋白构象的影响。     

Studies of interaction between colchicine and bovine serum albumin by fluorescence quenching method

We investigated the interaction between colchicine and bovine serum albumin (BSA) by fluorescence and UV–Vis absorption spectroscopy. In the mechanism discussion, it was proved that the fluorescence quenching of BSA by colchicine is a result of the formation of colchicine–BSA complex; van der Waals interactions and hydrogen bonds play a major role in stabilizing the complex. The modified Stern–Volmer quenching constant K_a and corresponding thermodynamic parameters ΔH, ΔG, ΔS at different temperatures were calculated. The distance r between donor (BSA) and acceptor (colchicine) was obtained according to fluorescence resonance energy transfer (FRET).     

表面修饰的硫化镉纳米粒子与牛血清白蛋白相互作用的荧光光谱研究

由于半导体纳米晶体独特的物理和化学特性,具有优良的光谱特征和光化学稳定性,其作为荧光生物探针,在生物学、医学方面的学术价值和良好的发展前景正引起科学工作者的广泛关注[1～3].     

桔皮苷与牛血清白蛋白相互作用的研究

运用荧光光谱、紫外光谱法研究了桔皮苷与牛血清白蛋白(BSA)的相互作用。桔皮苷分子与BSA作用导致BSA内源荧光猝灭,猝灭机理主要为静态猝灭,并存在非辐射能量转移。测定了不同温度下该反应的结合常数、结合位点数及结合热力学参数。结果表明:桔皮苷与BSA之间主要为氢键或范德华作用力,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;测得了供体与受体间结合距离r和能量转移效率E;并用同步荧光技术考察了桔皮苷对BSA构象的影响。     

胡椒酸丁二醇单脂与牛血清白蛋白相互作用的研究

运用荧光及紫外-可见吸收光谱法研究了胡椒酸丁二醇单酯(简称BPM)与牛血清白蛋白(BSA)的相互作用。实验结果表明,胡椒酸丁二醇单酯与BSA形成基态复合物导致BSA内源性荧光猝灭,猝灭机理主要为静态猝灭和非辐射能量转移,其猝灭速率常数为Kq为1.077×1013L/(mol.s)(25℃)、0.946×1013L/(mol.s)(37℃)。利用荧光猝灭反应测得结合常数KA为2.6×106(25℃)、3.4×106(37℃),结合位点数n为1.30(25℃)、1.33(37℃)。根据Frster能量转移理论得到结合距离r=2.92nm(25℃)、2.66nm(37℃)和能量转移效率E=0.45(25℃)、0.43(37℃)。通过热力学参数计算,确定胡椒酸丁二醇单酯与BSA的相互作用是熵增加和吉布斯自由能降低的自发过程,主要作用力是疏水作用力。     

甘草酸二铵与常态牛血清白蛋白相互作用的研究

应用光谱方法研究了甘草酸二铵(DAG)与牛血清白蛋白之间的相互作用,探讨了甘草酸二铵对牛血清白蛋白构象的影响.结果表明,甘草酸二铵对牛血清白蛋白荧光具有较强的猝灭作用且为静态猝灭过程.根据F(o)rster非辐射能量转移理论计算给体-受体间的距离(r=1.45 nm);得到结合常数(297K,K=1.14×105 L/...     

Study of the interaction between bovine serum albumin and ZnS quantum dots with spectroscopic techniques

The interaction between bovine serum albumin (BSA) and ZnS quantum dots (QDs) was studied by fluorescence, UV-vis spectroscopic techniques. The results showed that the fluorescence of BSA was strongly quenched by ZnS QDs and the quenching mechanism was discussed to be a static quenching procedure, which was proved by quenching rate constant K(q.) The recorded UV-vis data and the fluorescence data quenching by the QDs demonstrated that the interaction between them leads to the formation of QDs-BSA complex. Furthermore, the temperature effects on the structural and spectroscopic properties of individual QDs and protein and their bioconjugates (QDs-BSA) were also researched. It was found that, compared to the monotonically decrease of the individual QDs fluorescence intensity, the temperature dependence of the QDs-BSA emission had a much more complex behavior, highly sensitive to the conformational changes of the protein.     

Study on the interaction between antibacterial drug and bovine serum albumin: A spectroscopic approach

The binding of sulfamethoxazole (SMZ) to bovine serum albumin (BSA) was investigated by spectroscopic methods viz., fluorescence, FT-IR and UV–vis absorption techniques. The binding parameters have been evaluated by fluorescence quenching method. The thermodynamic parameters, ΔH°, ΔS°and ΔG° were observed to be −58.0 kJ mol⁻¹, −111 J K⁻¹ mol⁻¹ and −24 kJ mol⁻¹, respectively. These indicated that the hydrogen bonding and weak van der Waals forces played a major role in the interaction. Based on the Forster's theory of non-radiation energy transfer, the binding average distance, r, between the donor (BSA) and acceptor (SMZ) was evaluated and found to be 4.12 nm. Spectral results showed the binding of SMZ to BSA induced conformational changes in BSA. The effect of common ions and some of the polymers used in drug delivery for control release was also tested on the binding of SMZ to BSA. The effect of common ions revealed that there is adverse effect on the binding of SMZ to BSA.     

烷基咪唑型离子液体与牛血清白蛋白的相互作用研究

应用荧光光谱、紫外吸收光谱、傅立叶变换红外光谱和核磁共振波谱研究了烷基咪唑型离子液体[bmim][PF6]及其前体物质[bmim]Cl与牛血清白蛋白(BSA)分子间的相互作用.研究表明:在生理pH值条件下,[ bmim][ PF5]和[bmim] Cl均对BSA的内源性荧光产生猝灭,其猝灭程度[bmim][ PF6]＞...     

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,ΔGθ＜0,ΔHθ和ΔSθ分别为–12.60 kJ/mol 和 56.60 J/(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＝2.85 nm;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。     

Mechanism and conformational studies of farrerol binding to bovine serum albumin by spectroscopic methods

The mechanism and conformational changes of farrerol binding to bovine serum albumin (BSA) were studied by spectroscopic methods including fluorescence quenching technique, UV–vis absorption, circular dichroism (CD) spectroscopy and Fourier transform infrared (FT-IR) spectroscopy under simulative physiological conditions. The results of fluorescence titration revealed that farrerol could strongly quench the intrinsic fluorescence of BSA through a static quenching procedure. The thermodynamic parameters enthalpy change and entropy change for the binding were calculated to be −29.92 kJ mol⁻¹ and 5.06 J mol⁻¹ K⁻¹ according to the van’t Hoff equation, which suggested that the both hydrophobic interactions and hydrogen bonds play major role in the binding of farrerol to BSA. The binding distance r deduced from the efficiency of energy transfer was 3.11 nm for farrerol–BSA system. The displacement experiments of site markers and the results of fluorescence anisotropy showed that warfarin and farrerol shared a common binding site I corresponding to the subdomain IIA of BSA. Furthermore, the studies of synchronous fluorescence, CD and FT-IR spectroscopy showed that the binding of farrerol to BSA induced conformational changes in BSA.     

荧光光谱法研究氨曲南与牛血清白蛋白的相互作用

应用荧光光谱法及紫外可见光谱的方法研究了氨曲南与牛血清白蛋白(BSA)的相互作用.实验结果表明,氨曲南能强烈猝灭牛血清白蛋白的荧光强度,其荧光猝灭机理为动态猝灭.在此基础上计算了二者相互作用的结合常数、结合位点数及△H、△G、△S等热力学参数等.结果表明氨曲南与BSA以1:1结合,其反应为熵驱动,相互作用力主要为疏水力...     

苯溴马隆与牛血清白蛋白相互作用的研究

通过荧光光谱法和紫外吸收光谱法研究了模拟人体生理条件下苯溴马隆与牛血清白蛋白(BSA)的反应结合特征。结果表明,苯溴马隆对牛血清白蛋白的荧光具有静态猝灭作用,且用同步和三维荧光光谱研究了其对BSA构造的影响。通过F ster非辐射能量转移理论和Lineweave-Burk方程式分别得出了两者的作用距离、结合反应的结合常数和结合位点数。此外,还求算了结合过程的基本热力学参数。     

贝加因与牛血清白蛋白相互作用的分子光谱法研究

利用荧光光谱和吸收光谱研究了贝加因与牛血清白蛋白(BSA)的相互作用,由Van't Hoff方程计算了反应的热力学参数,并根据Stern-Volmer方程计算了不同温度下的结合位点和结合常数.结果表明,贝加因可静态猝灭BSA的内源荧光;二者相互作用的焓变和熵变均大于零,说明疏水作用力是二者之间的主要作用力.与此同时,贝...     

荧光光谱法研究辛硫磷与牛血清白蛋白的相互作用

用荧光光谱法研究了在生理pH条件下杀虫剂辛硫磷与牛血清白蛋白(BSA)的相互作用. 结果表明: 辛硫磷对BSA的荧光有较强的猝灭作用, 该猝灭属于静态猝灭. 根据猝灭结果求得了不同温度下辛硫磷与牛血清白蛋白结合作用的结合位点数、结合常数及反应热力学参数, 并据此确定它们之间主要的相互作用力为疏水作用力. 用同步荧光光谱法探讨了辛硫磷对BSA构象的影响.