线性扫描伏安法研究白杨素与牛血清白蛋白的相互作用

采用线性扫描伏安法研究了白杨素与牛血清白蛋白(BSA)之间的相互作用。优化的试验条件为:①以pH 7.40的磷酸氢二钠-磷酸二氢钠缓冲溶液为介质;②反应时间为20min;③反应温度为298K;④离子强度:1.0×10-3 mol·L-1氯化钠溶液。研究发现:白杨素与BSA在相互作用后形成了一种非电活性超分子化合物,转移系数(α)为0.121 9,表观电子传递速率常数(ks)为0.914s-1。     

荧光光谱法研究大豆甙元与牛血清白蛋白的相互作用

采用荧光光谱技术研究了大豆甙元与牛血清白蛋白(BSA)的相互作用.研究结果表明:290 K、303 K、310K、315 K温度下大豆甙元对BSA的猝灭速率常数Ksv随着温度升高逐渐降低,且均大于最大动态猝灭速率常数2×1010 L·mol -1·s-1,表明大豆甙元对BSA的荧光猝灭属静态猝灭过程.根据F(o)rst...     

大豆苷元与牛血清白蛋白的相互作用研究

采用荧光和紫外-可见吸收光谱,研究了大豆苷元与牛血清白蛋白(BSA)的相互作用.结果表明大豆苷元对BSA有较强的荧光猝灭作用;根据Stern-Volmer方程得到大豆苷元与BSA之间的结合常数KA为0.385×105 (30℃)、0.405×105(40℃)和0.431×105(50℃).根据F(o)rster非辐射能量转移理论,求出了大豆苷元与BSA之间的结合距离为2.34 nm(30℃)、2.48 nm(40℃)和2.71 nm(50℃).热力学数据表明大豆苷元与BSA之间的作用力主要为疏水作用力,同时用同步荧光光谱探讨了大豆苷元对BSA构象的影响.     

泛昔洛韦与牛血清白蛋白相互作用的伏安行为研究

在pH 7的B-R缓冲底液中,应用循环伏安法和微分脉冲法在玻碳电极上对泛昔洛韦与牛血清白蛋白相互作用进行了研究,与相同浓度单独存在于溶液中泛昔洛韦相比,峰电位基本不变,峰电流有所降低,讨论了pH、反应时间、扫速、富集时间、静止时间对二者作用的影响,建立了对牛血清白蛋白浓度的检测方法.计算了泛昔洛韦加入BSA前后转移的质子数和电子数不变,扩散系数变小,推测泛昔洛韦进入BSA的疏水空腔内,使游离药物浓度变小.     

抗坏血酸与牛血清白蛋白相互作用的电化学研究

应用电化学方法研究了在生理条件下:pH为7.30的0.1 mol/L的NaCl溶液中抗坏血酸(AA)与牛血清白蛋白(BSA)分子间的相互作用。研究表明:抗坏血酸与BSA形成了一种非电活性的生物超分子化合物,二者的结合常数为1.38×107L/mol,结合位点数为2。     

阿托伐他汀钙与牛血清白蛋白的相互作用

采用电化学方法并结合紫外、红外光谱分析, 研究了近生理pH 实验条件下新型抗血脂紊乱药物阿托伐他汀钙(AC)与牛血清白蛋白(BSA)的相互作用, 探讨了BSA对AC峰电流的增敏和减敏效应. 实验发现, 在pH为7.17的NaH₂PO₄-Na₂HPO₄缓冲溶液中, AC在静汞电极上产生一个还原峰, 加入BSA后峰电位发生移动且峰电流发生变化. 电化学研究结果表明, 部分疏水性AC小分子的芳香基团通过疏水作用镶嵌到BSA疏水微区内部, 使AC与BSA之间通过疏水作用力形成一种1:1的结合物, 结合常数为1.67×10⁵. 紫外吸收光谱结果表明,AC的加入使BSA的紫外吸收峰发生红移且有减色效应, 导致BSA 构象改变、α-螺旋含量减小. 红外光谱结果显示, AC与BSA分子中氨基酸残基的硫及氮原子形成键合作用.     

大黄酸与牛血清白蛋白相互作用的电化学研究

在pH3.5的Britton -Robinson缓冲液中 ,研究了大黄酸与牛血清白蛋白 (BSA)相互作用的电化学行为 ,二者结合生成了一种非电活性的超分子化合物。用循环伏安法和示差脉冲伏安法对该体系进行了研究 ,并对结合反应的机理进行了探讨。BSA的存在导致大黄酸氧化还原峰电流降低 ,峰电位基本不变 ,峰电流的下降值同所加入的BSA浓度在一定范围内呈线性关系。线性范围3.0×10 -8～8.0×10 -7mol/L ,检出限1.21×10 -8mol/L。     

邻苯二酚与牛血清白蛋白的相互作用

采用荧光和紫外光谱法研究了邻苯二酚同牛血清白蛋白(BSA)的作用.邻苯二酚对BSA内源荧光猝灭机理为静态猝灭,两者之间生成了不发荧光的复合物.根据双对数方程计算了复合物的结合常数KA和结合位点数n.确定邻苯二酚与BSA只有一个结合位点(可能位于Site I).通过热力学参数得出邻苯二酚与BSA之间主要作用力是疏水作用.同步荧光的结果表明邻苯二酚改变了BSA的分子构象,使色氨酸残基的极性增加,酪氨酸残基的疏水性增强.     

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...     

恩诺沙星与牛血清白蛋白的相互作用

恩诺沙星与牛血清白蛋白的相互作用;恩诺沙星;牛血清白蛋白;荧光猝灭     

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。     

Evaluation of the current function in linear sweep voltammetry by Pade approximation and epsilon convergence

Two procedures, viz., the epsilon convergence algorithm and Pade approximation scheme, are used to evaluate the current function values, graphical representation of the output, and verification of the model using existing data are carried out. For theoretical simulations of voltammograms, closed form of rational expressions using Pade approximant for the response of various reactions schemes involving soluble reactant and product, as well as coupled chemical process to an imposed linear scans were derived. Similarly, it was demonstrated epsilon convergence as an alternative procedure is much easier and elegant to use by an electroanalytical chemist with extreme ease.__________From Elektrokhimiya, Vol. 41, No. 4, 2005, pp. 482–500.Original English Text Copyright © 2005 by Sivakumar, Basha.This article was submitted by the authors in English.     

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...     

变色酸2B线性扫描伏安法测定血清白蛋白

用线性扫描伏安法研究了在pH3．0的Britton-Robinson(B-R)缓冲溶液中变色酸2B与蛋白质反应前后的电化学变化。在酸性溶液中变色酸2B在-0．48V(us．SCE)处有一个灵敏的伏安还原峰,当在溶液中加入人血清白蛋白后能够发生相互作用形成生物超分子复合物,使变色酸2B的伏安还原峰峰电流下降而峰电位基本保持不变。优化了结合反应条件和电化学测定条件,考察了常见干扰物质对测定的影响。在最佳条件下,峰电流的下降值同人血清白蛋白(HSA)的浓度在2．0～25．0mg／L范围内呈良好的线性关系,线性回归方程为△ip″(nA)=50．56ρ(mg／L)-6．72,相关系数r为0．995,检出限为1．84mg／L。将该方法应用于实际人血清样品的测定,结果与经典的考马斯亮蓝G-250光度法一致,回收率令人满意。     

光谱法研究吡嗪酰胺与牛血清白蛋白的相互作用

用光谱法研究了抗结核药吡嗪酰胺(Pyrazinamide,PZA)与牛血清白蛋白(bovine serum albumin,BSA)的相互作用,初步探讨了PZA对BSA的猝灭机理为静态猝灭,并用荧光猝灭法测定了作用的位点数n和结合常数K。根据不同温度下的热力学常数确定了PZA与BSA之间的作用力主要是氢键和范德华力作用。根据Forster非辐射能量转移原理,测定了实验条件下PZA与BSA相互结合时,能量授体-受体的结合距离。并用同步荧光和紫外光谱法研究了PZA对BSA构象的影响。     

Voltammetry determination of trace manganese with pretreatment glassy carbon electrode by linear sweep voltammetry

This paper described the determination of trace manganese using linear sweep voltammetry at a pretreatment glassy carbon electrode. The glassy carbon electrode pretreated by electrochemical method in the 0.1 mol l⁻¹ NaOH solution greatly improved the electrode responsibility in the determination of manganese(II). The barrier to the detection of low manganese concentration was overcome by means of autocatalytic effect of manganese oxide deposited on the electrode in advance. Under the optimum experiments condition (0.04 mol l⁻¹ NH₃-NH₄Cl buffer solution, pH 9.0), the linear range was 4×10⁻⁸ to 1×l0⁻⁶ mol l⁻¹ Mn(II) for linear sweep voltammetry and 1×10⁻⁹ to 4×10⁻⁸ mol l⁻¹ Mn(II) for convolution voltammetry. The relative standard deviation for 2×10⁻⁸ mol l⁻¹ Mn(II) is 3.4%. The proposed method is simple, rapid, sensitive and selective. It had been applied to the determination of trace manganese in samples with satisfactory results.     

An electrochemical sensing platform for trace analysis of Eriochrome Black T using multi-walled carbon nanotube modified glassy carbon electrode by adsorptive stripping linear sweep voltammetry

ABSTRACT

A highly sensitive electrochemical sensing platform was proposed for trace analysis of Eriochrome Black T in aqueous solutions by adsorptive stripping linear sweep voltammetry based on the open-circuit accumulation of Eriochrome Black T onto the fabricated multi-walled carbon nanotubes modified glassy carbon electrode surface. The proposed methodology was quite linear between 0.1 and 10 µM of Eriochrome Black T concentration with a correlation coefficient of 0.9981. The precision of the technique was acceptable with the relative standard deviations of lower than 13.4% for inter-day assays. In addition, the sensitivity properties of the proposed method were compared with those of the spectrophotometric method, which is frequently used in the literature for Eriochrome Black T analysis. The results showed that the proposed electrochemical sensing platform would be a more sensitive alternative to the existing spectrophotometric techniques. Finally, the methodology was successfully applied to the determination of Eriochrome Black T in a well water spiked at different concentration levels.     

Application of artificial neural networks to the determination of pesticides by linear sweep stripping voltammetry

In this work, artificial neural network (ANN), a powerful chemometrics approach for linear and nonlinear calibration models, was applied to detect three pesticides in mixtures by linear sweep stripping voltammetry (LSSV) despite their overlapped voltammograms. Electrochemical parameters for the voltammetry, such as scan rate, deposit time and deposit potential, were evaluated and optimized from the signal response data using ANN model by minimizing the relative prediction error (RPE). The proposed method was successfully applied to the detection of pesticides in synthetic samples and several commercial fruit samples.     

毛细管电泳应用于测定牛血清白蛋白与脂质体的相互作用

建立了一种用毛细管电泳法检测牛血清白蛋白(BSA)与脂质体相互作用的分析方法。氧化指数的测定实验结果表明经过冷冻干燥的脂质体稳定性更好;毛细管电泳表征脂质体的电荷性质实验结果表明脂质体在pH 5.0～8.0的条件下呈电中性。在pH 7.0的条件下,以各种浓度的脂质体混悬液为电泳缓冲液,以0.8%二甲亚砜(DMSO)为内标,随着缓冲液中脂质体质量浓度从0增加到2.4 mg/mL,BSA的有效淌度从-2.232×10-4 cm2·V－1·s－1变化到-3.046×10-4 cm2·V－1·s－1;结合Scatchard分析,测得BSA与脂质体的结合常数为2.522×103(g/mL)－1。该方法简单、快速,为研究蛋白质与脂质体的相互作用提供了新的技术手段。