氯诺昔康与牛血清白蛋白相互作用的光谱法研究

在模拟人体生理条件下,用荧光光谱法和紫外-可见吸收光谱法研究氯诺昔康(LNXC)和牛血清白蛋白(BSA)结合反应的特征.研究表明:氯诺昔康与牛血清白蛋白形成复合物,从而猝灭牛血清白蛋白的内源性荧光,该过程为静态猝灭过程.根据Stern-Volmer方程求出不同温度下结合位点数和结合常数;根据Forster非辐射能量转移...     

Studies on the interaction of CdTe QDs with bovine serum albumin

BACKGROUND: Quantum dots (QDs) have attracted much attention in biological and medical applications. In particular, the interaction of QDs with bovine serum albumin (BSA) is crucial, and has been systematically investigated by various spectroscopic techniques under the physiological conditions. RESULTS: The effects of ionic strength and pH on the interaction of CdTe QDs with BSA were studied by changing NaCl concentration and pH in mixed solution and making fluorescence spectroscopic measurements. The Stern‐Volmer quenching constant (K_a) of different ionic strength and pH were calculated, and information on the structural features of BSA were discussed by means of circular dichroism (CD) spectrum. CONCLUSION: Both fluorescence (FL) and circular dichroism (CD) results indicated that hydrophobic and electrostatic interactions play a major role in the binding reaction, and the nature of quenching is static, resulting in forming QDs‐BSA complexes. Copyright © 2012 Society of Chemical Industry     

甲基对硫磷与牛血清白蛋白相互作用的光谱研究

[目的]为了解释有机磷农药—甲基对硫磷对牛血清白蛋白(BSA)的作用与致毒机理。[方法]采用紫外和荧光光谱法研究甲基对硫磷与BSA的相互作用。[结论]甲基对硫磷能与BSA相互作用,其作用程度和方式与浓度、酸度和离子强度等因素有关。甲基对硫磷对BSA的荧光猝灭方式为静态猝灭,通过计算得到结合位点数(n)和结合常数(K),且结合距离(r)小于7 nm。二者的作用力为氢键或范德华力。甲基对硫磷使BSA构象发生变化,且对酪氨酸残基的影响较大。     

荧光法研究两面针总生物碱与牛血清蛋白的相互作用

利用荧光光谱法研究了不同温度、离子强度、酸度及共存金属离子存在下,两面针总生物碱(tAZN)与牛血清白蛋白(BSA)之间的相互作用。结果表明,随着温度的升高,tAZN对BSA的荧光猝灭程度降低,推测tAZN对BSA的猝灭作用为静态猝灭过程。同时也考察了内源环境(pH、离子强度)及共存金属离子对tAZN与BSA相互作用的影响;tAZN与BSA以静电力发生相互作用;静电力在药物发挥抗癌功能时可发挥一定作用。     

Photoprocesses of chlorin e6 bound to lysozyme or bovin serum albumin

The ground and excited state processes of chlorin e6 in aqueous solution were studied in the presence of lysozyme and also bovine serum albumin. Non-covalent binding to proteins was analyzed using fluorescence, UV–visible and circular dichroism absorption spectroscopy. The number of binding sites, n, was 1.5–2.4 and the apparent macroscopic dissociation constant, K_d was 0.2–2.5 μM. The binding of chlorin e6 to lysozyme, in contrast to that of bovine serum albumin, imparted fluorescence quenching; circular dichroism spectra revealed a chiral environment upon binding to β-sheets of bovine serum albumin. Time-resolved photolysis showed a longer triplet lifetime upon interaction with the proteins owing to shielding of the dye. The quantum yields for both damage to chlorin e6 (Φ_d) and for protein oxidation (Φ_ox) were determined under oxygen-free conditions; Φ_d was smaller because of shielding by the protein with respect to the self-quenching of the free dye. The major effects concerning photooxidation in the absence and presence of oxygen are discussed.     

荧光光谱法研究姜黄素与牛血清白蛋白的相互作用

考察了姜黄素与牛血清白蛋白(BSA)的相互作用机制。利用荧光光谱考察了两者之间的荧光淬灭类型,计算结合数(n)和结合常数,结果显示姜黄素与BSA作用可导致BSA发生静态淬灭,采用Stern-Volmer拟合方程测得结合常数Ka=4.52×108L/mol,结合位点数n=1.62。姜黄素可与牛血清白蛋白发生结合,导致牛血清蛋白发生静态荧光淬灭。     

中药活性成分山萘酚与牛血清白蛋白相互作用的研究

应用光谱法研究了中药活性成分山萘酚(Kaempferol)与牛血清白蛋白(BSA)的相互作用,探讨了山萘酚对BSA的荧光猝灭过程的机理,测定了不同温度下该结合反应的结合模式、结合常数、结合位点数、结合热力学参数等；并利用经典位点探针试剂华法林(Warfarin)和布洛芬(Ibuprofen)研究了山萘酚与BSA作用的具...     

A study of the binding of C.I. Mordant Red 3 with bovine serum albumin using fluorescence spectroscopy

The interaction of C.I. Mordant Red 3 and bovine serum albumin was investigated using fluorescence and UV–vis absorption spectroscopy. Fluorescence quenching, from which binding parameters were evaluated, revealed that the quenching of the serum by C.I. Mordant Red 3 resulted from the formation of a dye–serum complex. The enthalpy and entropy changes for the reaction were ?50.49 kJ mol^?1 and ?50.88 J mol^?1 K^?1 respectively. van der Waals forces and hydrogen bonds were the dominant intermolecular forces that stabilize the complex; the distance between donor and acceptor was 2.79 nm, according to Förster's non-radiative energy transfer theory. The effect of the dye upon the conformation of bovine serum albumin was analyzed using synchronous fluorescence spectrum.     

荧光光谱法研究核黄素与牛血清白蛋白的相互作用

荧光光谱法研究了注射用核黄素(Riboflavin,Rf)与牛血清白蛋白(BSA)的相互作用.核黄素对BSA具有荧光猝灭作用,其猝灭方式为静态猝灭;在301和317K下用Stem-Volmer方程和热力学方程等处理实验数据,求出了结合常数KA、结合位点数n及热力学参数ΔG、ΔH和ΔS.核黄素与BSA之间的作用力主要为氢...     

Fluorescent amino-substituted squaraine probes for bovine serum albumin

The synthesis and spectroscopic properties of fluorescent amino-substituted squaraine dyes have been presented. The interaction between bovine serum albumin (BSA) and fluorescence probes derived from squaric acid was studied by UV-vis and fluorescence spectroscopies. The Benesi–Hildebrand, Lehrer, and Stern–Volmer equations were used to present the influence of BSA concentration on the binding constant for the process of association with squaraine dyes, as well as the effect of the concentration of fluorescence probes on the quenching process. It was also shown that the interaction between BSA and squaraine dyes is spontaneous. The number of binding sites to bovine serum albumin for a series of squaraine dyes has also been calculated.     

维C和左氧氟沙星对白蛋白的荧光淬灭研究

通过荧光光谱法研究了在维生素C存在下左氧氟沙星对牛血清白蛋白的荧光淬灭作用。在模拟生理条件（pH=7.4,37℃）下,根据Stem-Volmer方程,确定了在维生素C存在条件下,左氧氟沙星与牛血清白蛋白的淬灭类型仍为静态淬灭,左氧氟沙星对牛血清白蛋白的荧光淬灭减弱,结合常数和结合位点均变小。为研究左氧氟沙星和维生素对蛋白质构象的影响等提供了重要信息。     

锡离子（Ⅳ）与牛血清白蛋白相互作用的研究

应用荧光光谱和紫外可见吸收光谱研究了锡离子（Ⅳ）与牛血清白蛋白间的结合作用,确定了锡离子（Ⅳ）对牛血清白蛋白的荧光猝灭过程的猝灭机理.测定了不同温度下该结合反应的结合常数,结合位点数,热力学参数.依据能量转移理论确定了锡离子（Ⅳ）和白蛋白间的结合距离.采用同步荧光技术考察了锡离子（Ⅳ）对牛血清白蛋白构象的影响,并讨论了锡离子（Ⅳ）与白蛋白的结合模式.实验结果表明猝灭机理是动态猝灭,锡离子（Ⅳ）与BSA以物质的量比1∶1的比例结合形成复合物,结合过程主要是熵驱动,相互作用主要为疏水作用力.     

苯甲酸与牛血清白蛋白相互作用的荧光光谱研究

采用荧光光谱、三维荧光光谱、同步荧光光谱研究了苯甲酸与牛血清白蛋白(BSA)分子之间的相互作用机制、特征及苯甲酸对牛血清白蛋白构象的影响。根据不同温度下苯甲酸对牛血清白蛋白的荧光猝灭作用,利用Stem-Volmer和Lineweaver-Burk方程和热力学方程分别处理实验数据,求得它们之间的结合常数K为1.096×103L/mol、结合位点数n为1.12(20℃),ΔH=-31.8 kJ/mol,ΔG=-17.1 kJ/mol,ΔS=-50.2 J.mol-1.K-1。研究发现苯甲酸对BSA内源性荧光的猝灭作用属于静态猝灭,苯甲酸与BSA分子之间的相互作用是一个吉布斯自由能降低的自发过程,两者之间的主要作用力类型为氢键力或范德华力。     

血竭总黄酮与血清白蛋白的作用

应用荧光光谱法研究不同离子强度、温度、酸度条件下,血竭总黄酮(tFSD)与血清白蛋白的相互作用。研究表明:tFSD能不同程度地猝灭牛血清白蛋白(BSA)和人血清白蛋白(HSA)的荧光强度,BSA的荧光强度猝灭得更显著;在288~298K间,随着温度的升高,BSA-tFSD和HSA-tFSD两荧光体系的猝灭程度降低,推测tFSD对BSA、HSA的荧光猝灭作用不是动态猝灭,而是静态猝灭;在pH6.0~pH10.0间,随着pH的提高,tFSD对BSA(HSA)的荧光猝灭程度上升,说明tFSD与BSA(HSA)之间以非静电作用为主,并形成了不发荧光的复合物。     

L-半胱氨酸与牛血清白蛋白相互作用的荧光光谱分析

运用荧光猝灭光谱、同步荧光光谱探讨了L-半胱氨酸（L-Cys）与牛血清白蛋白（BSA）的相互作用,并计算了猝灭常数、结合常数、结合位点数以及3个热力学参数△H、△G和△S。结果表明,L-Cys使BSA的内源荧光发生猝灭,BSA的发射峰从350nm蓝移到347．5nm,荧光猝灭机制为动态猝灭;L-Cys与BSA之间的作用力主要为疏水作用力;L-Cys对BSA结构的微环境有一定的影响。     

光谱法研究蛋白质与胆红素及铜的相互作用

应用荧光光谱研究了胆红素(BR)及铜与牛血清白蛋白(BSA)的相互作用机制.结果表明,BSA-BR的光谱图在有Cu2 存在时,发生了明显的变化,表明能够形成BSA-Cu2 -BR三元络合物.胆红素主要以静态猝灭的方式使得牛血清白蛋白荧光强度显著降低,胆红素和牛血清白蛋白主要凭借范德华力和氢键作用结合.测定了BSA-BR、BSA-Cu2 以及BSA-Cu2 -BR体系的组成和结合常数.探讨了铜离子及胆红素与牛血清白蛋白间的结合反应,阐明了铜离子浓度对胆红素和蛋白质结合的影响.     

一种新型喹唑啉酮衍生物A与牛血清白蛋白作用的研究

应用荧光光谱和紫外可见吸收光谱研究了A与牛血清白蛋白间的结合作用,确定了A对牛血清白蛋白的荧光猝灭过程的猝灭机理。测定了不同温度下该结合反应的结合常数,结合位点数,热力学参数。依据能量转移理论确定了A和蛋白间的结合距离。采用同步荧光技术考察了A对牛血清白蛋白构象的影响,并讨论了A与蛋白的结合模式。     

荧光光谱法研究左氧氟沙星、拉米夫定同时与牛血清白蛋白的相互作用

在模拟生理条件(pH值为7.40的Tris-HCl缓冲溶液)下,应用荧光光谱法研究了左氧氟沙星和拉米夫定对牛血清白蛋白(BSA)的荧光猝灭过程。结果表明:BSA与2种药物发生强烈猝灭,主要是静态猝灭;2种药物之间存在着相互作用,一种药物的存在提高了另一种药物与BSA之间结合的稳定性,减少了游离药物含量,药效降低。左氧氟沙星和拉米夫定之间的相互作用为临床合理用药提供了帮助。     

荧光光谱法研究二氢卟吩e6和锌二氢卟吩e6与牛血清白蛋白的相互作用

应用紫外光谱和荧光光谱法研究二氢卟吩e6(Ce6)和锌二氢卟吩e6(ZnCe6)分别与牛血清白蛋白(BSA)的相互作用。通过紫外光谱、荧光光谱、光照实验,探讨了两种物质与BSA相互作用的荧光猝灭光谱特征、猝灭机理、与BSA结合反应及光照的影响。结果表明,Ce6和ZnCe6都可与BSA发生相互作用,Ce6和ZnCe6浓度的变化会引起Ce6、ZnCe6与BSA之间能量转移的变化,Ce6的猝灭程度要比ZnCe6强,猝灭机制是由静态猝灭引起的。Ce6与BSA的结合能力强于锌二氢卟吩e6,结合位点数均接近1,结合的作用力类型主要为范德华力和氢键作用力。Ce6-BSA和ZnCe6-BSA复合物均有光漂白特性,光漂白机制均为光学修饰型引起的,这种机制有利于提高光动力治疗(PDT)效果。     

Characterization of interaction between C.I. Acid Green 1 and human serum albumin: Spectroscopic and molecular modeling method

The binding characteristics of human serum albumin with C.I. Acid Green 1 were studied by employing fluorescence, resonance light scattering, ultraviolet–visible, circular dichroism, Fourier transform infrared techniques and molecular modeling. Spectroscopic analysis has revealed that quenching of human serum albumin by C.I. Acid Green operates by a static quenching mechanism. The results by Fourier transform infrared, circular dichroism and ultraviolet–visible absorption spectra experiment indicated that the secondary structures of protein were changed in the presence of C.I. Acid Green 1. Molecular modeling revealed that a dye–protein complex was stabilized by hydrophobic forces, Van-der-Waals force and hydrogen bonding, via amino acid residues. Furthermore, influences of coexisting substances on the binding constant of C.I. Acid Green 1-human serum albumin complexes were investigated.