杀鼠剂溴鼠灵与牛血清白蛋白相互作用的光谱法研究

利用紫外吸收光谱,荧光光谱和同步荧光技术研究了牛血清白蛋白和杀鼠剂溴鼠灵的相互作用.结果表明溴鼠灵对牛血清白蛋白的内源荧光有较强的猝灭作用,两者形成了新的复合物,属于静态荧光猝灭,并且伴随着分子内的非辐射能量转移.通过双倒数及双对数曲线计算了不同温度下的猝灭速率常数Ksv,结合位点数n,结合常数KA,并根据相对应的热力学参数判断二者之间主要为疏水作用力.依据F(o)rster非辐射能量转移理论求出了溴鼠灵和蛋白质问的结合距离r,确定了溴鼠灵在蛋白质上的结合位置.在20和30℃时r分别为2.84和2.87 nm.同步荧光光谱显示,与溴鼠灵作用后BSA分子的二级结构发生了改变.初步探讨了二者的结合模式与作用机制:溴鼠灵分子通过静电引力靠近蛋白质的疏水腔,并以疏水作用力与疏水腔中的氨基酸残基发生相互作用,导致色氨酸残基微环境极性变化.其结果不但阻止了酪氨酸残基与色氨酸残基间的能量转移,而且使色氨酸残基与溴鼠灵分子间产生非辐射能最转移,从而猝灭BSA的内源荧光.     

Spectroscopic Studies on the Toxic Interaction of Sodium Oleate with Bovine Serum Albumin

The effects of sodium oleate on Bovine Serum Albumin (BSA) were investigated by fluorescence, synchronous fluorescence, ultraviolet–visible and circular dichroism spectroscopy. According to the experiment results, we found that the fluorescence intensity of BSA was quenched by sodium oleate following a static mode, a sodium oleate-BSA complex was formed and the binding site was calculated approximately equal to 1. The experimental results showed that the hydrophilic group (—COONa) can bind to the BSA and lead to the looser of the protein conformation, the microenvironment and the secondary structure elements were changed in the presence of sodium oleate. This work reflected the toxic interaction mechanism of BSA and sodium oleate from the perspective of spectroscopy.     

Spectroscopic Studies on the Interaction of Acid Yellow With Bovine Serum Albumin

Azo dyes, which are common in the environment, can be toxic to various organisms. In order to determine the molecular mechanism of acid yellow 11(AY) toxicity, we studied the effect of AY exposure to the common protein bovine serum albumin (BSA) by several spectroscopic techniques including fluorescence spectroscopy, ultraviolet spectrophotometry (UV) and circular dichroism (CD). It could be concluded from the fluorescence spectra that the quenching effect of BSA by AY was mainly due to complex formation which was unrelated to the absorption of AY. The enthalpy change (ΔH) and entropy change (ΔS) were found to be −21.94 kJ/mol and 30.04 Jmol^-1 K^-1, respectively. The results confirm that electrostatic attraction was the predominant intermolecular force between BSA and AY. Furthermore, the binding distance (r) between AY and the inner tryptophan residue of BSA was determined to be 3.541 nm on the basis of Forster theory of non-radiative energy transfer. In addition, the conformational changes of BSA in the presence of AY were also analyzed by UV and CD. These results indicated that AY could interact with BSA by complex formation, which also affected the structure of BSA.     

光谱法研究儿茶素与牛血清白蛋白的相互作用

运用荧光猝灭光谱、傅里叶红外光谱(FTIR)等光谱手段研究了模拟人体牛理条件下儿茶素与牛血清白蛋白(bovine serum albumin,BSA)的相互作用,求出了儿茶素与BSA结合的结合常数、结合位置、结合类型等参数,并研究了共存离子对儿茶素与BSA的结合常数的影响.实验结果表明:儿茶素与BsA形成复合物从而猝灭BSA的内源荧光,且其荧光猝灭机理符合静态机制.296,303,310 K下儿茶素与BSA结合的结合常数分别为:2.368,2.249,2.152×106 L·mol-1.热力学数据表明儿茶素与BsA主要靠疏水作用力和静电作用力结合,探针实验表明儿茶素与BSA在结合位点Site Ⅰ发生结合.F(o)ster偶极一偶极非辐射能量转移机理确定了儿茶素在BSA中与第214位色氨酸残基之间的距离r=1.93 nm.FTIR光谱显示,儿茶素诱导BSA的二级结构发生了变化.     

光谱法比较木犀草素及槲皮素与牛血清白蛋白相互作用

在模拟生理pH条件下,采用荧光光谱、紫外-可见吸收光谱、同步荧光光谱和圆二色谱法研究木犀草素及槲皮素与牛血清白蛋白（BSA）的相互作用的异同.结果确定木犀草素及槲皮素对BSA的荧光猝灭是以静态猝灭为主,同时伴随非辐射能量转移猝灭.木犀草素结合BSA的位点与荧光发射基团的距离比槲皮素的小.结合常数Ka表明二者与BSA的结合都属于强的非共价键结合,且结合位点数都约为1.二者均主要通过氢键和范德华力与BSA作用.二者都能影响BSA的酪氨酸残基附近环境的极性,且高浓度下能够引起BSA构象轻微地改变.结果表明黄酮C环上3位羟基的引入会降低其对BSA的亲和力.     

Fluorescence Study of Sinapic Acid Interaction with Bovine Serum Albumin and Egg Albumin

The mechanism of interaction of protein with compounds used for preparation of matrices for matrix-assisted laser desorption ionization–mass spectrometry (MALDI-MS) methods is unknown. This paper reports the investigation of this mechanism for sinapic acid and bovine serum albumin and egg albumin. To examine these interactions in water a fluorescence method was applied. Sinapic acid can exist in three different forms, depending on pH: undissociated and with one or two deprotonated groups. pK_as of these states are: 4.47 for the COOH group and 9.21 for the OH group [1]. Therefore the interactions were examined at pH: 2.0, 6.4, and 10.5. The results show that sinapic acid at pH 10.5, being a bivalent anion, does not form any complex with these two proteins. At pH 2.0, sinapic acid, being undissociated, interacts weakly with egg albumin. Sinapic acid does not interact with bovine serum albumin at this pH. At pH 6.4, sinapic acid interacts only with bovine serum albumin. Parameters of the sinapic acid and bovine serum albumin complex were calculated based on the theory of multiple equlibria: the total number of binding sites, N = 15; the binding constant, K = 600 M ^–1; and the Hill's coefficient, j = 0.97. These parameters indicate (but not definitively because a large saturation was not obtained) that this is a simple binding of sinapic acid to bovine serum albumin with the binding sites of the same type.     

Fluorescence Study on the Interaction of Bovine Serum Albumin with P-Aminoazobenzene

In this paper, the interaction between p-aminoazobenzene (PAAB) and BSA was investigated mainly by fluorescence quenching spectra, circular dichroism (CD) and three-dimensional fluorescence spectra under simulative physiological conditions. It was proved that the fluorescence quenching of BSA by PAAB was mainly a result of the formation of a PAAB-BSA complex. The modified Stern-Volmer quenching constant K _a and the corresponding thermodynamic parameters ΔH, ΔG and ΔS at different temperatures were calculated. The results indicated that van der Waals interactions and hydrogen bonds were the predominant intermolecular forces in stabilizing the complex. The distance r?=?4.33 nm between the donor (BSA) and acceptor (PAAB) was obtained according to Förster’s non-radioactive energy transfer theory. The synchronous fluorescence, CD and three-dimensional fluorescence spectral results showed that the hydrophobicity of amino acid residues increased and the losing of α-helix content (from 63.57 to 51.83%) in the presence of PAAB. These revealed that the microenvironment and conformation of BSA were changed in the binding reaction.     

粉防己碱与牛血清白蛋白相互作用的研究

利用荧光光培和紫外-可见吸收光谱,研究了粉防己碱与BSA相瓦作用的光谱学行为.研究结果表明,粉防己碱埘BSA有较强的荧光猝灭作用,静态猝灭和非辐射能量转移是导致粉防己碱猝火BSA内源荧光的主要原因.利用Stern-Volmer方程处理实验数据,获得了猝火常数Ksv,不同温度下的Ksv分别为1.26×104 L·mol-1(300 K),1.17×104 L·mol-1(310 K),1.12×104 L·mol-1(320 K).根据Forster非辐射能量转移理论计算出了粉防己碱与BSA间的结合距离r(300 K:3.24 nm;310 K:3.31 nm;320 K:3.50nm).此外,还求得了粉防己碱与BSA的结合常数KA(300 K:1.52×105 L·mol-1;310 K:2.03×105 L·mol-1;320 K:2.89×105 L·mol-1)及相应温度下的热力学参数,热力学数据表明二者主要靠疏水作用力结合.粉防己碱与BSA相互作用的同步荧光光谱表明,二者的结合对BSA构象产生了影响.     

对硝基苯酚与牛血清白蛋白相互作用的荧光光谱研究

在模拟生理条件下应用荧光光谱和紫外-可见吸收光谱技术研究了牛血清白蛋白(BSA)与对硝基苯酚的相互作用.通过修正Stern-Volmer方程求算出在不同温度下(304,307,310K)的淬灭常数为1.186,1.030,0.940×105 L·mol-1,证实了BSA与对硝基苯酚相互结合作用为单一的静态猝灭过程,并且得到对硝基苯酚与BSA相互作用的热力学参数△H0和△S0分别为-28.061kJ·mol-1和-14.331J·mol-1·K-1,推出两者的相互作用以氢键为主.根据非辐射能量转移理论,计算出对硝基苯酚与BSA相互结合时其供体-受体间的结合距离(r=5.94nm)和能量转移效率(E=0.09).     

Study on the Interaction between Florasulam and Bovine Serum Albumin

In this paper, the interaction between florasulam (FU, 2′,6′,8-trifluoro-5-methoxy [Kragh-Hansen U, Molecular aspects of ligand binding to serum albumin. Pharmacol Rev 33(1):17–53 1981; Carter DC and Ho JX, Structure of serum albumin. Adv Protein Chem 45:153–203 1994; He XM, and Carter DC, Atomic structure and chemistry of human serum albumin. Nature 358(6383):209–215 1992] triazolo [1,5-c]pyrimidine-2-sulfonanilide) and bovine serum albumin (BSA) was investigated by fluorescence, ultraviolet absorption (UV) and Far-UV circular dichroism (CD) spectrometries. A strong fluorescence quenching was observed and the quenching mechanism was considered as static quenching. The binding constant of FU with BSA at 299 and 309 K were obtained as 1.5?×?10⁴ and 7.1?×?10³ l mol^?1, respectively. There was one binding site between FU and BSA. The thermodynamic parameters enthalpy change (ΔH) and entropy change (ΔS) were calculated as ?57.89 kJ mol^?1 and ?113.6 J mol^?1 K^?1, respectively, which indicated that the acting force between FU and BSA was mainly hydrogen bond and Van der Waals force. According to the Förster non-radiation energy transfer theory, the average binding distance between donor (BSA) and acceptor (FU) was obtained (r?=?1.59 nm). The investigations of the UV/Vis and CD spectra of the system showed that the conformation of BSA was changed in presence of FU.     

荧光法研究可可碱与牛血清白蛋白的相互作用

采用荧光光谱法研究了可可碱这种生物碱药物与牛血清白蛋白(BSA)分子间的相互结合反应。测定了可可碱与BSA反应的结合平衡常数K和结合位点数n,并用同步荧光光谱技术考察了可可碱对牛血清白蛋白构象的影响。证实了可可碱药物与牛血清白蛋白的相互结合作用为单一的静态猝灭过程,可可碱的加入对牛血清白蛋白的构象有影响。     

光谱法研究酸度对一种白杨素衍生物与牛血清白蛋白相互作用的影响

在3种酸度条件下,采用多种光谱技术对一种白杨素衍生物和牛血清白蛋白的相互作用进行了研究.结果表明该衍生物和牛血清白蛋白可形成基态复合物,静态、动态猝灭方式同时存在,以静态猝灭为主.通过计算获得了在不同温度及酸度条件下的结合常数及结合位点数.该衍生物在碱性条件下和牛血清白蛋白的结合能力较强.在pH 7.40的生理条件下,...     

对硝基苯胺与牛血清白蛋白的相互作用

采用荧光光谱法研究了不同酸度下对硝基苯胺与牛血清白蛋白(BSA)间的相互作用.实验结果表明,对硝基苯胺能与BSA形成复合物而导致BSA内源性荧光猝灭,猝灭机理为静态猝灭过程.经计算得到了不同酸度和不同温度下对硝基苯胺与BSA反应的结合常数、结合位点数.结合过程的热力学参数变化表明,该相互作用是一个熵增加、Gibbs自由能降低的自发作用过程,其作用力类型主要为静电作用力.     

ANS与牛血清白蛋白的相互作用

通过荧光光谱研究了8-苯胺基-1-萘磺酸(ANS)在牛血清白蛋白(BSA)上的结合位置、结合常数及作用力,通过计算ANS分子的一些参数,发现芳环上引入磺酸基更有助于ANS与蛋白的作用.     

大黄酸及大黄素和牛血清白蛋白的相互作用

采用荧光猝灭和红外光谱方法考察了两种大黄蒽醌类化合物(大黄酸和大黄素)与模型蛋白牛血清白蛋白之间的相互作用.结果表明,大黄酸和大黄素主要通过静电作用与牛血清白蛋白形成基态化合物,从而使其内部荧光猝灭,并获得了二者相互作用的结合常数、结合位点数及大黄酸和大黄素与色氨酸结合的空间距离.金属离子对这两种大黄蒽醌类化合物与牛血...     

乙二胺-N,N′-二邻氨基苯甲酸与牛血清白蛋白作用的荧光光谱研究

在pH7.4,0.05mol.L-1Tris-HCl条件下,采用荧光光谱法研究了乙二胺-N,N′-二邻氨基苯甲酸(EDA)与牛血清白蛋白(BSA)的相互作用。结果表明,EDA与BSA的结合使蛋白质的荧光被猝灭,条件稳定常数为lgK=5.81±0.04,结合位点数为1,并依据Foerster能量转移理论确定EDA与BSA色氨酸残基的最近距离r为2.14nm。     

TNS与牛血清白蛋白相互作用的荧光光谱研究

在pH 7.0、20mmol·L-1磷酸盐缓冲溶液(PB)及室温条件下,利用荧光光谱研究了药物模拟物TNS与牛血清白蛋白的作用.结果表明TNS与牛血清白蛋白有一个强结合位点,其条件结合常数为 (4.86±0.14)×105L·mol-1;结合主要以疏水作用为主,静电结合也起一定作用;依据Forster能量转移机制得到授体-受体间距离r=2.10nm;该条件下被环糊精包结的TNS也可以转化为TNS-牛血清白蛋白复合物.     

核黄素与牛血清A蛋白相互作用的研究

运用荧光光谱法研究了核黄素(Riboflavin,Rf)与牛血清白蛋白(BSA)的作用机制.结果表明:Rf对BSA具有荧光猝灭作用,其猝灭方式为静态猝灭,求出了猝灭常数、结合常数及结合位点数.还研究了Zn2+对核黄素与BSA作用的影响,Zn2+的加入使得核黄素与BSA的结合常数与结合位点数减小.     

淫羊藿苷与牛血清白蛋白相互作用

在模拟人体生理条件下,采用荧光光谱法及紫外-可见吸收光谱法研究了淫羊藿苷与牛血清白蛋白的相互作用。结果表明,淫羊藿苷对牛血清白蛋白有较强的猝灭作用,猝灭方式为静态猝灭。当温度为25℃和36℃时,淫羊藿苷对牛血清白蛋白的猝灭速率常数分别为4.37×10¹²mol·L^-1·s^-1和3.90×10¹²mol·L^-1·s^-1,结合常数K_A为3.55×10⁴L·mol^-1和3.97×10⁴L·mol^-1,结合位点数为1.12和1.04;根据Foerster非辐射能量转移理论,计算出淫羊藿苷与牛血清白蛋白之间的结合距离为2.08nm,热力学分析表明,淫羊藿苷与牛血清白蛋白之间以疏水作用力为主。