培氟沙星-铽(Ⅲ)-牛血清白蛋白体系的荧光光谱及其应用

在pH 8.2的Tris-HCl缓冲溶液中, Tb3+与培氟沙星(PEFX)形成的配合物受290 nm紫外光激发发出Tb3+的特征荧光峰, 加入牛血清白蛋白(BSA)能大大增强体系的荧光强度, 由此建立了PEFX-Tb3+ 配合物探针测定BSA的方法. 与PEFX-Tb3+二元配合物相比, PEFX-Tb3+-BSA三元体系荧光强度显著增强. 研究了反应的最佳条件, 并对PEFX-Tb3+-BSA荧光增强作用的机理进行了探讨.     

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.     

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.     

荧光光谱法研究克仑特罗与蛋白质的结合作用

应用荧光光谱法研究了水溶液中盐酸克仑特罗与牛血清白蛋白分子间的结合反应 ,测定了结合常数 (K =2 .84× 1 0 3 L mol)和结合位点数 (n =5 .65)。依据F ster非辐射能量转移理论 ,确定了授体 受体间的结合距离 (r=1 .69nm)和能量转移效率 ,采用同步荧光技术考察了盐酸克仑特罗对牛血清白蛋白构象的影响。利用盐酸克仑特罗对蛋白质荧光猝灭 ,对作用机理做了初步探讨     

头孢噻肟-Cu(Ⅱ)-牛血清白蛋白相互作用的荧光光谱法研究

用荧光光谱法研究了生理酸度条件下,头孢噻肟对牛血清白蛋白,Cu(Ⅱ)对牛血清白蛋白以及Cu(Ⅱ)对头孢噻肟和牛血清白蛋白荧光光谱特性的影响。结果表明:Cu(Ⅱ)和头孢噻肟均可使牛血清白蛋白的荧光强度发生静态猝灭,并且在Cu(Ⅱ)存在下,头孢噻肟对牛血清白蛋白的荧光猝灭作用显著增强。根据荧光猝灭双倒数图计算头孢噻肟和牛血清白蛋白的结合常数为3.11×104L/mol,结合位点数为1.03;二元配合物Cu(Ⅱ)与牛血清白蛋白之间的结合常数为1.13×103L/mol,结合位点数为0.74。     

荧光猝灭法研究胆红素与牛血清白蛋白的相互作用

在模拟生理条件下,利用荧光猝灭法研究了胆红素(BR)和牛血清白蛋白(BSA) 的相互作用.结果表明胆红素对BSA有较强的荧光猝灭作用,两者形成了新的复合物,属于静态荧光猝灭,发生了分子内的非辐射能量转移.计算了不同温度下的结合位点数n,结合常数KA,以及对应的热力学参数ΔG,ΔH和ΔS.根据Foster非辐射能量转移理论确定了胆红素和BSA间的结合距离r.此外,利用同步荧光光谱,分析了胆红素对牛血清白蛋白构象的影响.     

中药黄连有效成分盐酸小檗碱与牛血清白蛋白的相互作用

从天然中药材黄连中提取分离并精制得到盐酸小檗碱(BC),采用UV光谱和荧光光谱(FS)研究其与牛血清白蛋白(BSA)的相互作用,解释了BC导致BSA的荧光发射光谱峰裂分的现象,其二重峰分别归属于色氨酸及酪氨酸残基.结果表明,静态猝灭和非辐射能量转移是导致BC对BSA荧光猝灭的两大原因,BC与BSA的表观结合常数K_A为8.66×10⁴L/mol(30℃)和8.72×10⁴L/mol(37℃),BC在BSA分子上的结合位点数为(3.1±0.2).BC与BSA分子中荧光性氨基酸残基之间的距离为3.75nm(30℃)和3.62nm(37℃),表明BC的部分片段能够插入BSA分子内部.热力学函数计算结果表明,该作用过程是一个熵增加、Gibbs自由能降低的自发超分子作用过程,并由此推断BC与BSA之间以疏水相互作用为主.     

Spectrometric study of the interaction between Alpinetin and bovine serum albumin using chemometrics approaches

The binding interaction of Alpinetin (APT) with bovine serum albumin (BSA) was studied by fluorescence, UV-visible and synchronous fluorescence spectroscopy (SFS) under simulated physiological conditions. The measured complex spectra were resolved by multivariate curve resolution-alternating least squares (MCR-ALS), yielding a host of data and information, which otherwise would have been impossible to obtain. The extracted profiles corresponded to the spectra of the single species in the APT/BSA mixture. In addition, the presence of the APT-BSA complex was demonstrated, and it was shown that the associated quenching of the fluorescence from the BSA protein resulted from the formation of APT-BSA complex via a static mechanism. The binding constant (K_a(ave) = 2.34 × 10⁶ L mol⁻¹) and the number of sites (n = 1) were obtained by fluorescence methods as were the thermodynamic parameters (ΔH⁰, ΔS⁰ and ΔG⁰). This work suggested that the principal binding between APT to BSA was facilitated by hydrophobic interactions. The thermodynamic parameters for APT were compared to those from the structurally similar Chrysin and Wogonin molecules. It appeared that the entropy parameters were relatively more affected by the small structural changes. SFS from the interaction of BSA and APT showed that the ligand affected the conformation of BSA. The competitive interaction of APT and site makers with BSA indicated site I as the binding area of APT in BSA.     

Affinity capillary electrophoresis and fluorescence spectroscopy for studying enantioselective interactions between omeprazole enantiomer and human serum albumin

Baseline separation of omeprazole (OME) enantiomers was achieved by affinity capillary electrophoresis (ACE), using human serum albumin (HSA) as the chiral selector. The influence of several experimental variables such as HSA concentration, the type and content of organic modifiers, applied voltage and running buffer concentration on the separation was evaluated. The binding of esomeprazole (S‐omeprazole, S‐OME) and its R‐enantiomer (R‐omeprazole, R‐OME) to HSA under simulated physiological conditions was studied by ACE and fluorescence spectroscopy which was considered as a reference method. ACE studies demonstrated that the binding constants of the two enantiomers and HSA were 3.18 × 10³ M⁻¹ and 5.36 × 10³ M⁻¹, respectively. The binding properties including the fluorescence quenching mechanisms, binding constants, binding sites and the number of binding sites were obtained by fluorescence spectroscopy. Though the ACE method could not get enough data when compared with the fluorescence spectrum method, the separation and binding studies of chiral drugs could be achieved simultaneously via this method. This study is of great significance for the investigation and clinical application of chiral drugs.     

Studies on Reaction Mechanism Between Sparfloxacin and Bovine Serum Albumin

The binding of sparfloxacin and bovine serum albumin(BSA) in aqueous solution was studied by means of fluorescence and absorbance spectra, and the interactions influenced by Fe^3 and Cu^2 were explored. Based on the Scatchard‘s site binding model and fluorescence quenching, practical formulas for a small molecule ligand attaching to a bio-macromolecule are proposed. The binding parameters were measured according to the suggested models, and the binding distance, the transfer efficiency of energy between sparfloxacin and BSA were obtained in view of the F6rster theory of non-radiation energy transfer. The effect of sparfloxacin on the conformation of BSA was analyzed by means of synchronous fluorescence spectroscopy.     

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...     

荧光法研究奥沙利铂与牛血清白蛋白的相互作用

在Tris缓冲溶液(pH7.0)体系中,用荧光光谱及同步荧光光谱技术研究水溶液中奥沙利铂与牛血清白蛋白的相互作用。结果表明,奥沙利铂对牛血清白蛋白内源荧光(345nm)产生较强的荧光猝灭作用,根据不同温度下奥沙利铂对牛血清白蛋白的荧光猝灭作用,证明其为静态猝灭机制,运用位点模型计算出298、308K时结合常数KA(分别为4.22×104、3.95×104L.mol-1)和结合位点数n(分别为1.02、1.01),根据热力学参数确定其作用力以静电作用为主;运用Fster偶极-偶极非辐射能量转移原理,测定了奥沙利铂与牛血清白蛋白的结合距离r(5.67nm);用同步荧光技术考察了奥沙利铂对牛血清白蛋白构像的影响。     

光谱法研究巯嘌呤与血清白蛋白的相互作用

利用荧光光谱和紫外-可见光谱法研究了巯嘌呤药物与牛血清白蛋白(BSA)和人血清白蛋白(HAS)分子间的相互结合反应.测得巯嘌呤与BSA、HAS反应的结合平衡常数分别为:2.39×103L/mol、1.28×103L/mol.根据Forster非辐射能量转移理论,求算了给体(BSA和HAS)与受体(巯嘌呤)间的结合距离和能量转移效率.用同步荧光法考察了巯嘌呤对BSA和HAS构象的影响.证实了巯嘌呤药物与牛血清白蛋白和人血清白蛋白的相互结合作用为单一的静态猝灭过程.     

Facile, sensitive and selective fluorescence turn-on detection of HSA/BSA in aqueous solution utilizing 2,4-dihydroxyl-3-iodo salicylaldehyde azine

A novel fluorescence turn-on detection method of human serum albumin (HSA) and bovine serum albumin (BSA) in aqueous solution is investigated using 2,4-dihydroxyl-3-iodo salicylaldehyde azine (DISA). Upon the addition of DISA to HSA/BSA solution, a fluorescence turn-on effect at 529 nm can be observed with a large stokes shift of ∼129 nm based on hydrophobic binding-mode between protein and dye. Under the optimal condition, the linear ranges of fluorescence intensity for HSA and BSA are 0.1-30 μg mL⁻¹ with the relative correlation coefficient of R² = 0.991 (n = 10) and 0.3-50 μg mL⁻¹ with R² = 0.997 (n = 10); and the detection limits for HSA and BSA based on IUPAC (C_DL = 3S_b/m) are 20 ng mL⁻¹ and 50 ng mL⁻¹, respectively.     

Tracing the origin of extra virgin olive oils by infrared spectroscopy and chemometrics: A case study

In this paper, the potential of coupling mid- and near-infrared spectroscopic fingerprinting techniques and chemometric classification methods for the traceability of extra virgin olive oil samples from the PDO Sabina was investigated. To this purpose, two different pattern recognition algorithm representative of the discriminant (PLS-DA) and modeling (SIMCA) approach to classification were employed. Results obtained after processing the spectroscopic data by PLS-DA evidenced a rather high classification accuracy, NIR providing better predictions than MIR (as evaluated both in cross-validation and on an external test set). SIMCA confirmed these results and showed how the category models for the class Sabina can be rather sensitive and highly specific. Lastly, as samples from two harvesting years (2009 and 2010) were investigated, it was possible to evidence that the different production year can have a relevant effect on the spectroscopic fingerprint. Notwithstanding this, it was still possible to build models that are transferable from one year to another with good accuracy.     

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...     

荧光光谱法研究原花青素与牛血清白蛋白的相互作用

在pH=7.40的Tris-HCl缓冲体系中,采用荧光光谱技术研究了原花青素与牛血清白蛋白(BSA)的相互作用.根据295 K、303 K、310 K、315 K温度下的猝灭常数,表明原花青素对BSA的荧光猝灭为静态猝灭过程,由热力学参数焓变(△rHm)和熵变(△rSm)均大于零,推断出原花青素与BSA之间主要靠疏水作...     

川陈皮素与牛血清白蛋白相互作用的光谱研究

用多种光谱技术研究了生理条件下川陈皮素(NOB)与牛血清白蛋白(BSA)的相互作用及热力学特征.结果表明,NOB与BSA有较强的作用,NOB能使BSA的内源荧光猝灭,并以静态猝灭为主.按照Stern-Volmer方程和双对数方程分别得出不同温度下,以及不同pH值时NOB与BSA的结合常数和结合位点数.运用紫外光谱获得常温下NOB与BSA的结合常数与荧光光谱测定值相近,热力学参数△H、△S分别为55.91 kJ·5moL~(-1)、274.61 J·5moL~(-1)·5K-1,表明其主要作用力为疏水力,NOB与BSA作用为非辐射能量转移机制,其能量转移效率与结合距离分别为0.27和1.76 nm,用参比法得出BSA荧光量子产率为0.074.同步荧光光谱研究发现川陈皮素对牛血清白蛋白构象几乎没有影响.     

荧光光谱法研究木犀草素与牛血清白蛋白的相互作用

在pH为7.40的Tris-HCl缓冲体系中,采用荧光光谱技术研究了木犀草素与牛血清白蛋白(BSA)的相互作用。根据测定292K、299K、311K温度下的猝灭常数,证实了木犀草素对BSA的荧光猝灭为静态猝灭过程,根据Frster非辐射能量转移理论计算出木犀草素与BSA间的结合距离r=2.75nm,由热力学参数焓变(△H)小于零和熵变(△S)大于零,推断出木犀草素与BSA之间主要靠静电引力相结合,生成自由能变(△G)为负值,表明木犀草素与BSA的作用过程是一个自发过程;同时,应用同步荧光光谱考察了木犀草素对BSA构象的影响。     

Interaction between Janus Green B and bovine serum albumin:Electrochemistry and spectroscopy studies

In this study,voltammetric and spectroscopic investigation of the interaction between Janus Green B(JGB) and bovine serum albumin(BSA) was reported.The interaction was observed at Britton-Robinson buffer(pH 7.0).When JGB was added to solution containing BSA,the peak currents of BSA decrease with the increasing of JGB concentrations which is due to the interaction of JGB and BSA.The binding constant of JGB with BSA was obtained by voltammetric data.Also,this interaction was supported by means of UV-vis spectroscopic measurements.The UV-vis absorption spectra of JGB in the presence of BSA decrease with the increasing of BSA concentrations.