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1.
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Frster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。 相似文献
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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。 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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Boghaei DM Farvid SS Gharagozlou M 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,66(3):650-655
Circular dichroism (CD) spectroscopy, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to investigate the interaction between copper(II) complex of compartmental Schiff base ligand (L), N,N'-bis(3-hydroxysalicylidene)ethylenediamine, and bovine serum albumin (BSA) in 0.1 mol dm(-3) phosphate buffer solution adjusted to physiological pH 7.0 containing 20% (w/w) dimethylsulfoxide at room temperature. CD spectra show that the interaction of the copper(II) complex with BSA leads to changes in the alpha-helical content of BSA and therefore changes in secondary structure of the protein with the slight red shift (2 nm) in CD spectra. From the voltammetric data, i.e. changes in limiting current with addition of BSA, the binding constant (K) of the interaction of copper(II) complex with BSA was found to be 1.96 x 10(4)dm(3)mol(-1). From the shifts in potential with the addition of BSA, the equilibrium constant ratio (K(2)/K(1)) for the binding of the oxidized Cu(II)L (K(1)) and reduced Cu(I)L (K(2)) species to BSA was found to be 3.77, which shows that the reduced form Cu(I)L is bound more strongly to BSA than the oxidized form Cu(II)L. 相似文献
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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Frster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。 相似文献
7.
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/... 相似文献
8.
光谱法研究甲芬那酸与蛋白质的相互作用 总被引:9,自引:0,他引:9
用UV Vis吸收光谱和荧光光谱法研究了在模拟人体生理条件下,甲芬那酸与牛血清白蛋白结合反应特征,发现甲芬那酸对牛血清白蛋白有较强的荧光猝灭作用,且甲芬那酸的紫外吸收光谱和牛血清白蛋白的荧光发射光谱有一定程度的重叠,由此得出了其结合反应的结合常数、结合位点数和结合过程的基本热力学参数。 相似文献
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Spectroscopic studies on the interaction between 3,4,5-trimethoxybenzoic acid and bovine serum albumin 总被引:1,自引:0,他引:1
Hu YJ Yu HG Dong JX Yang X Liu Y 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(3-4):988-992
The interaction between 3,4,5-trimethoxybenzoic acid (TMBA) and bovine serum albumin (BSA) was studied by fluorescence and UV-vis absorption spectroscopy. In the mechanism discussion, it was proved that the fluorescence quenching of BSA by TMBA is a result of the formation of TMBA-BSA complex. Quenching constants were determined using the Stern-Volmer equation to provide a measure of the binding affinity between TMBA and BSA. The thermodynamic parameters DeltaH, DeltaG, DeltaS at different temperatures were calculated, and electrostatic interactions play an important role to stabilize the complex. The distance r between donor (BSA) and acceptor (TMBA) was obtained according to fluorescence resonance energy transfer (FRET). 相似文献
12.
Gao J Guo Y Wang J Wang Z Jin X Cheng C Li Y Li K 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(4):1278-1286
In this work, three o-Vanillin Schiff Bases (o-VSB: o-Vanillin-D-Phenylalanine (o-VDP), o-Vanillin-L-Tyrosine (o-VLT) and o-Vanillin-L-Levodopa (o-VLL)) with alanine constituent were synthesized by direct reflux method in ethanol solution, and then were used to study the interaction to bovine serum albumin (BSA) molecules by fluorescence spectroscopy. Based on the fluorescence quenching calculation, the bimolecular quenching constant (K(q)), apparent quenching constant (K(sv)), effective binding constant (K(A)) and corresponding dissociation constant (K(D)) as well as binding site number (n) were obtained. In addition, the binding distance (r) was also calculated according to Foster's non-radioactive energy transfer theory. The results show that these three o-VSB can efficiently bind to BSA molecules, but the binding array order is o-VDP-BSA>o-VLT-BSA>o-VLL-BSA. Synchronous fluorescence spectroscopy indicates that the o-VDP is more accessibility to tryptophan (Trp) residues of BSA molecules than to tyrosine (Tyr) residues. Nevertheless, the o-VLT and o-VLL are more accessibility to Tyr residues than to Trp residues. 相似文献
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《Journal of photochemistry and photobiology. A, Chemistry》2007,185(2-3):271-276
The interaction of 18β-glycyrrhetinic acid (GA): The metabolite of glycyrrhizic acid which is the main active component of a commonly used traditional Chinese medicine (TCM) Glycyrrhiza Uralensis Fisch with bovine serum albumin (BSA) has been investigated. Fluorescence emission spectra of serum albumin in the presence of GA, recorded at the excitation wavelength 280 nm, clearly show that GA act as quencher and have different quenching mechanism at a pH below or above the isoelectric point (pI). The binding sites number n and apparent binding constant K were measured. The thermodynamic parameters ΔH°, ΔG°, ΔS° at different temperatures were calculated. The effects of some common metal ions on binding are considered. Synchronous fluorescence and UV–vis spectra were used to study protein conformation. Energy transfer between GA and HSA was calculated by Förster's theory and the binding site was suggested to be site II. The binding of monoammonium glycyrrhizinate (GL) to BSA is also compared. 相似文献
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The interaction between apigenin (Ap) and bovine serum albumin (BSA) in physiological buffer (pH = 7.4) is investigated by
fluorescence quenching technique and UV-vis absorption spectra. The results reveal that Ap could strongly quench the intrinsic
fluorescence of BSA. The quenching mechanism of Ap for BSA varies with the change of Ap concentration. when Ap concentration
is lower, it is a static quenching procedure, when Ap concentration is higher, a combined quenching (both static and dynamic)
would operate. The apparent binding constants Ka and number of binding sites n of Ap with BSA are obtained by fluorescence
quenching method. The thermodynamic parameters, enthalpy change (Δr
H
m
and entropy change (Δr
S
m
), are calculated to be −15.382 kJ mol−1 K−1 < 0 and 104.888 J mol−1 K−1 > 0, respectively, which indicate that the interaction of Ap with BSA is driven mainly by hydrogen bonding and hydrophobic
interactions. The distance r between BSA and Ap is calculated to be 1.89 nm based on F?rster’s non-radiative energy transfer theory. The results of synchronous
fluorescence spectra show that binding of Ap with BSA cannot induce conformational changes in BSA. 相似文献
16.
Gharagozlou M Boghaei DM 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,71(4):1617-1622
Fluorescence spectroscopy in combination with circular dichroism (CD) spectroscopy were used to investigate the interaction of water-soluble amino acid Schiff base complexes, [Zn(L1,2)(phen)] where phen is 1,10-phenanthroline and H2L1,2 is amino acid Schiff base ligands, with bovine serum albumin (BSA) under the physiological conditions in phosphate buffer solution adjusted to pH 7.0. The quenching mechanism of fluorescence was suggested as static quenching according to the Stern-Volmer equation. Quenching constants were determined using the Stern-Volmer equation to provide a measure of the binding affinity between amino acid Schiff base complexes and BSA. The thermodynamic parameters DeltaG, DeltaH and DeltaS at different temperatures (298, 310 and 318K) were calculated. The results indicate that the hydrophobic and hydrogen bonding interactions play a major role in [Zn(L1)(phen)]-BSA association, whereas hydrophobic and electrostatic interactions participate a main role in [Zn(L2)(phen)]-BSA binding process. Binding studies concerning the number of binding sites and apparent binding constant Kb were performed by fluorescence quenching method. The distance R between the donor (BSA) and acceptor (amino acid Schiff base complexes) has been obtained utilizing fluorescence resonant energy transfer (FRET). Furthermore, CD spectra were used to investigate the structural changes of the BSA molecule with the addition of amino acid Schiff base complexes. The results indicate that the interaction of amino acid Schiff base complexes with BSA leads to changes in the secondary structure of the protein. Fractional contents of the secondary structure of BSA (f(alpha), f(beta), f(turn) and f(random)) were calculated with and without amino acid Schiff base complexes utilizing circular dichroism spectroscopy. Our results clarified that amino acid Schiff base complexes could bind to BSA and be effectively transported and eliminated in the body, which could be a useful guideline for further drug design. 相似文献
17.
Kalyanmoy Jana Somnath Das Tithi Maity Maidul Hossain Subhas Chandra Debnath 《Journal of Coordination Chemistry》2018,71(10):1497-1509
A new Co(II) complex of general formula [Co(L)2] has been synthesized from a NNO tridentate Schiff base ligand, 2-[(piperidin-2-ylmethylimino)-methyl]-phenol (L). The title complex is characterized by elemental, spectroscopic, antibacterial, and single crystal X-ray structural studies. X-Ray crystallography reveals that the complex shows a distorted octahedral geometry around the Co(II) ion. The complex was tested against several bacteria and shows good antibacterial activities against almost all of the bacteria. The interactions of the title complex with calf thymus deoxyribonucleic acid (CT-DNA) have been investigated by electronic absorption and fluorescence spectroscopy, showing that the complex interacts with CT-DNA via partial intercalation. Thermogravimetric analysis (TGA) of the complex has also been reported and the result shows that the complex is thermally stable up to 134 °C. 相似文献
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Binding of the vitamin folic acid with bovine serum albumin (BSA) has been studied using isothermal titration calorimetry (ITC) in combination with fluorescence and circular dichroism spectroscopies. The thermodynamic parameters of binding have been evaluated as a function of temperature, ionic strength, in the presence of nonionic surfactants triton X-100, tetrabutylammonium bromide, and sucrose. The values of the van’t Hoff enthalpy calculated from the temperature dependence of the binding constant agree with the calorimetric enthalpies indicating that the binding of folic acid to the BSA is a two state process without involving intermediates. These observations are supported by the intrinsic fluorescence and circular dichroism spectroscopic measurements. With increase in the ionic strength, reduction in the binding affinity of folic acid to BSA is observed suggesting predominance of electrostatic interactions in the binding. The contribution of hydrophobic interactions in the binding is also demonstrated by decrease in the binding affinity in the presence of tetrabutylammonium bromide (TBAB). The value of binding affinity in the presence of sucrose indicates that hydrogen bonding also plays a significant contribution in the complexation process. The calorimetric and spectroscopic results provide quantitative information on the binding of folic acid to BSA and suggest that the binding is dominated by electrostatic interactions with contribution from hydrogen bonding. 相似文献
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The interactions between oleanolic acid and bovine serum albumin (BSA) have been studied by fluorescence, circular dichroism (CD), UV–vis absorption and Fourier transform infrared spectroscopy (FTIR) under physiological conditions. Spectroscopic analysis of the emission quenching at different temperatures has revealed that the quenching mechanism of bovine serum albumin by oleanolic acid is static quenching mechanism. The binding sites number n and binding constants K are obtained at various temperatures. The distance r between oleanolic acid and the protein is evaluated according to the theory of Forster energy transfer. The results by FTIR, CD and UV–vis absorption spectra experiment indicate that the secondary structures of protein have been perturbed in the presence of oleanolic acid. The thermodynamic parameters ΔH0, ΔG0, and ΔS0 are calculated according to van’t Hoff equation, which indicates that the hydrogen bonds and van der-waals are the intermolecular forces stabilizing the complex. Molecular modeling studies the interaction BSA with oleanolic acid. 相似文献