糖精钠与牛血清白蛋白相互作用的荧光光谱研究

在模拟人体生理条件下,应用荧光和紫外-可见光谱法研究了糖精钠与牛血清白蛋白(BSA)之间的相互作用;并计算了不同温度下的热力学参数、结合常数和结合位点数.结果表明,糖精钠对BSA的猝灭机制属于形成复合物的静态猝灭过程;两者之间的作用主要是氢键或范德华力,作用的位点更靠近色氨酸;金属离子对两者的作用具有一定的影响.     

Denaturation of bovine serum albumin under the action of cetyltrimethylammonium bromide, according to data from fluorescence analysis

The tryptophan fluorescence of bovine serum albumin (BSA) in solutions with different concentrations of cationic detergent cetyltrimethylammonium bromide (CTAB) at different pH is investigated, providing information on BSA denaturation under the action of CTAB. It is found that BSA denaturation under the action of CTAB at all of the investigated pH values (3.5–8.0) is a single-stage process, as determined by BSA tryptophan fluorescence quenching, by an increased degree of the BSA tryptophan fluorescence polarization, and by the values of the parameters for the rotational diffusion of BSA molecules in CTAB solutions. It is shown that the cationic detergent CTAB is more efficient for BSA denaturation at pH values higher than the BSA isoelectric point (4.9).     

Chiral resolution of tryptophan derivatives by CE using canine serum albumin and bovine serum albumin as chiral selectors

This work deals with the application of BSA and canine serum albumin (CSA) for enantioseparation of tryptophan derivatives with CE. The aim of this work was the investigation of the influence of different functional groups of tryptophan derivatives on enantioseparation. CSA as a chiral selector was tested to compare its selector properties with those of BSA. The enantiomers of the tryptophan derivatives were separated by adding BSA or CSA to the BGE. The influence of pH, temperature, BSA and CSA concentration and organic modifiers was investigated. It was found that the stereoselectivity for the different tryptophan derivatives is dependent on the albumin species. It turned out that the different functional groups of the derivatives showed a significant influence on stereoselectivity.     

荧光光谱法研究4-硝基苯胺与牛血清白蛋白的相互作用

在模拟动物生理条件下利用荧光光谱法从分子水平上研究了4-硝基苯胺同牛血清白蛋白(BSA)的相互作用.4-硝基苯胺对BSA的荧光有较强猝灭作用.用Stern-Volmer方程和双对数方程分别处理实验数据发现BSA与4-硝基苯胺发生反应生成了新的复合物,猝灭机理以静态碎灭为主.根据双对数方程求出了不同温度下反应时复合物的形...     

灯盏花素与牛血清白蛋白相互作用的荧光光谱研究

采用荧光光谱法和紫外吸收光谱法研究了灯盏花素(BR)与牛血清白蛋白(BSA)的相互作用;利用热力学方程计算了295K和308K下的热力学参数ΔH、ΔG和ΔS,根据Stern-Volmer方程求出了猝灭常数和结合常数.结果表明,BR对BSA的荧光具有猝灭作用,其猝灭机制为动态-静态联合猝灭,BSA发射峰略有蓝移.BR与BSA之间的作用力主要为疏水作用.     

Binding of naproxen to bovine serum albumin and tryptophan-modified bovine serum albumin

Two classes of binding sites, a single high-affinity site with an association constant of 4·8×10⁶ M⁻¹ and two low-affinity sites with association constant of about 0·05×10⁶ M⁻¹ have been observed in the interaction of Naproxen with bovine serum albumin (BSA). Chemical modification of two tryptophan residues in BSA with 2-hydroxy-5-nitrobenzyl bromide has led to a reduction in the association constant of the high-affinity site by 89% and its number of binding sites by 66% suggesting the involvement of tryptophan residues in the high-affinity site. In contrast, the two low-affinity sites were not affected by the modification. Binding of Naproxen to the low-affinity sites of BSA induces microdisorganisation of the albumin structure leading to conformational changes as evident from fluorescence measurements with 1-anilino-8-naphthalenesulphonic acid as the probe.     

荧光共振能量转移测定牛血清白蛋白的研究

随着生物分析技术进入了后基因组时代,生命科学领域里的研究课题不断深入,DNA、RNA、蛋白质和其他生物大分子的检测技术发展十分迅速,生命科学中单分子分析技术不断揭示出生命活动的客观规律.相关的新的分析方法和仪器不断取得进展,成为生命科学的前沿领域.     

荧光光谱法研究牛血清蛋白在尿素体系中的变性

应用荧光光谱技术,对尿素与牛血清蛋白在30℃水溶液中的结合作用及造成牛血清蛋白变性的过程进行了研究,获取了尿素诱导牛血清蛋白变性时相对荧光强度和峰位的变化规律.用Pace等提出的公式分析了相对荧光强度数据,得到了牛血清蛋白变性时的伸展分数fu随溶液pH值和尿素浓度的变化规律.求出了变性平衡常数Ku,伸展吉布斯自由能△G...     

荧光共振能量转移测定牛血清白蛋白的研究

随着生物分析技术进入了后基因组时代,生命科学领域里的研究课题不断深入,DNA、RNA、蛋白质和其他生物大分子的检测技术发展十分迅速,生命科学中单分子分析技术不断揭示出生命活动的客观规律.相关的新的分析方法和仪器不断取得进展,成为生命科学的前沿领域.     

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.     

Rotational diffusion of fluorescein family markers in solutions of human serum albumin

Rotational diffusion of fluorescein family nanomarkers (initial fluorescein and its halogenated derivatives, eosin and erythrosine) in solutions of human serum albumin (HSA) was studied at various pH values. In solutions of HSA, the degree of fluorescence polarization, rotational relaxation time, and Einstein radius of nanomarkers are larger and the rotational diffusion coefficient of nanomarkers smaller than in solutions without the protein. An increase in the electronegativity of atoms in the structural formulas of nanomarkers increases the degree of polarization of their fluorescence, decreases the coefficient of their rotational diffusion, and increases rotational relaxation time and the effective Einstein radius.     

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).     

荧光光谱法研究拉贝洛尔与牛血清白蛋白相互作用特征

应用荧光光谱和紫外-可见吸收光谱研究了拉贝洛尔与牛血清白蛋白(Bovine Serum Albumin,BSA)结合反应的光谱学特征.实验结果表明,在弱酸性条件下拉贝洛尔对BSA的猝灭机理为静态猝灭,而在中性和弱碱性时则为动态猝灭;根据 F(o)rster非辐射能量转移理论计算出310K和pH7.41时拉贝洛尔与BSA...     

Selective quenching of tryptophanyl fluorescence in bovine serum albumin by the iodide ion

Modified Stern-Volmer equation is obeyed by bovine serum albumin (BSA)-iodide system showing selective quenching of tryptophanyl fluorescence of BSA. The fraction of accessible protein fluorescence is 0.56 and the effective Stern-Volmer constant is 290 M^-1 at pH 7.4 in 0.005 M phosphate buffer at 25°C. Collisional quenching is operative both in the BSA -I⁻¹ system and the model system, tryptophan-I⁻¹. It is supported by the observed relationship between the ratio of quenching rate constants (k _q ) and diffusion coefficients and alsok _q with bulk viscosity.     

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。     

Binding of the bioactive component daphnetin to human serum albumin demonstrated using tryptophan fluorescence quenching

Daphnetin (7,8-dihydroxycoumarin), one of the major bioactive components isolated from Daphne koreane Nakai, has been used in traditional Chinese medicine for the treatment of coagulation disorders. It is also a chelator, an antioxidant and a protein kinase inhibitor. In this paper, a combination of intrinsic fluorescence, Fourier transform infrared (FT-IR) spectroscopy and circular dichroic (CD) spectroscopy has been used to characterize the binding between daphnetin and human serum albumin (HSA) under physiological conditions with drug concentrations of 6.7 x 10(-6) - 2.3 x 10(-5) mol x L(-1), and a HSA concentration of 1.5 x 10(-6) mol x L(-1). Changes in the CD spectra and FT-IR spectra were observed upon ligand binding, and the degree of tryptophan fluorescence quenching did change significantly in the complexes. These data have proved the change in protein secondary structure accompanying ligand binding. The change in tryptophan fluorescence intensity was used to determine the binding constants. The thermodynamic parameters, the enthalpy change (DeltaH) and the entropy change (DeltaS) were calculated to be -12.45 kJ x mol(-1)and 52.48 J x mol(-1) x K(-1) according to the van't Hoff equation, which indicated that hydrophobic and electrostatic interactions played the main role in the binding of daphnetin to HSA, in accordance with the results of calculations performed on a Silicon Graphics Ocatane2 workstation. In addition, the binding distance between daphnetin and HSA was obtained (4.02 nm) based on the Forster energy transfer theory.     

光谱法研究尼泊金乙酯钠与牛血清白蛋白的相互作用

在模拟生理条件下(pH=7.40),应用荧光光谱、吸收光谱和同步荧光光谱法探讨了不同温度下尼泊金乙酯钠(Ethylparaben Sodium,EPS)与牛血清白蛋白(Bovine Serum Albumin,BSA)相互作用的机制.荧光光谱和吸收光谱分别表明:尼泊金乙酯钠对BSA内源荧光有明显猝灭作用,属于静态猝灭,二者的猝灭作用是由于尼泊金乙酯钠与BSA形成基态复合物导致的.运用双对数方程求得291、310 K时的结合常数分别为3.23×106、3.63×105L·mol-1,结合位点数分别为0.99和0.84.运用热力学方程得出热力学参数(ΔH,ΔS),通过ΔH0,ΔS0可知二者之间的作用力主要是氢键或范德华力.同步荧光光谱表明尼泊金乙酯钠对BSA结构的构象会产生影响.本研究为EPS的毒理和生物学效应提供了重要的参考信息.     

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。     

荧光光谱法研究左西孟旦与牛血清白蛋白的结合反应

用荧光光谱法、分光光度法研究了水溶液中左西孟旦与牛血清白蛋白(BSA)的相互结合反应。研究表明:左西孟旦对BSA的内源荧光有较强的猝灭作用且该猝灭作用属于静态荧光猝灭作用。得出了反应的结合常数(KA=1.48×106L/mol)和结合位点数(n=1.14)。根据Frster非辐射能量转移机理,求算了给体(BSA)与受体(左西孟旦)间距离r=2.9 nm和能量转移效率E=0.33。     

Investigation of the association behaviors between biliverdin and bovine serum albumin by fluorescence spectroscopy

The interaction between biliverdin and bovine serum albumin (BSA) has been studied by steady fluorescence spectroscopy, synchronous fluorescence and resonance light scanning spectra. The binding of biliverdin to BSA quenches the tryptophan residue fluorescence and the results show that both static and dynamic quenching occur together with complex formation. The binding constant and binding sites of biliverdin to BSA at pH 7.1 are calculated to be 3.33 × 10⁸ L/mol and 1.54, respectively, according to the double logarithm regression curve. In addition, the distance between the biliverdin and BSA is estimated to be 1.25 nm using Föster's equation on the basis of the fluorescence energy transfer. Furthermore the synchronous fluorescence spectra show that the microenvironment of the tryptophan residues has not obvious changes, which obeys the phase distribution model. Finally, the thermodynamic data show that biliverdin molecules enter the hydrophobic cavity of BSA via hydrophobic interaction.