Study of the interaction between N-confused porphyrin and bovine serum albumin by fluorescence spectroscopy

The fluorescence and ultraviolet spectroscopy were explored to study the interaction between N-confused porphyrins (NCP) and bovine serum albumin (BSA) under imitated physiological condition. The experimental results indicated that the fluorescence quenching mechanism between BSA and NCP was static quenching procedure at low NCP concentration at 293 and 305 K or a combined quenching (static and dynamic) procedure at higher NCP concentration at 305 K. The binding constants, binding sites and the corresponding thermodynamic parameters ΔH, ΔS, and ΔG were calculated at different temperatures. The comparison of binding potency of the three NCP to BSA showed that the substituting groups in benzene ring could enhance the binding affinity. From the thermodynamic parameters, we concluded that the action force was mainly hydrophobic interaction. The binding distances between NCP and BSA were calculated using F?rster non-radiation energy transfer theory. In addition, the effect of NCP on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy.     

Mechanistic investigation on binding interaction of bioactive imidazole with protein bovine serum albumin--a biophysical study

The interaction between bioactive imidazole derivative (PPP) and bovine serum albumin (BSA) was investigated using fluorescence and UV-vis spectral studies. The experimental results showed that the fluorescence quenching of BSA by imidazole derivative was the result of the formation of BSA-PPP complex and the effective quenching constants (K(SV)) were 2.66×10(4), 2.56×10(4), and 2.10×10(4) at 301, 310 and 318 K, respectively. Static quenching and non-radiative energy transfer were confirmed to the result in the fluorescence quenching. The binding site number n, apparent binding constant K(A) and corresponding thermodynamic parameters (ΔG, ΔH and ΔS) were measured at different temperatures. The process of binding of PPP molecule on BSA was a spontaneous molecular interaction procedure in which entropy increased and Gibbs free energy decreased.     

Study on the interaction between salvianic acid A sodium and bovine serum albumin by spectroscopic methods

The interaction between salvianic acid A sodium (SAS) and bovine serum albumin (BSA) was investigated using fluorescence and ultraviolet spectroscopy at different temperatures under imitated physiological conditions. The experimental results showed that the fluorescence of BSA was quenched by SAS through a static quenching procedure. The binding constants of SAS with BSA were 2.03, 1.17 and 0.71×10(5) L mol(-1) at 291, 298 and 305 K, respectively. Negative values of ΔG, ΔH, and ΔS indicate that the interaction between SAS and BSA is driven by hydrogen bonds and van der Waals forces. According to F?rster non-radiation energy transfer theory, the binding distance between BSA and SAS was calculated to be about 2.92 nm. The effect of SAS on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy. In addition, the effect of some metal ions Cu(2+), Ca(2+), Mg(2+), and Zn(2+) on the binding constant between SAS and BSA was examined.     

Spectroscopic studies on the interaction between nicotinamide and bovine serum albumin

The interaction of nicotinamide (NA) and bovine serum albumin (BSA) was studied by fluorescence and absorption spectroscopy at different temperatures. The results revealed that NA caused the fluorescence quenching of BSA through a static quenching procedure. The binding constants K(A), and the number of binding sites n, corresponding thermodynamic parameters DeltaG, DeltaH, DeltaS between NA and BSA at different temperatures were calculated. The primary binding pattern between NA and BSA was interpreted as hydrophobic interaction. In addition, the effect of NA on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy. The binding average distance, r between the donor (BSA) and acceptor (NA) was determined based on the F?rster's theory and it was found to be 3.1 nm.     

Binding of the bioactive component isothipendyl hydrochloride with bovine serum albumin

The binding of isothipendyl hydrochloride (IPH) to bovine serum albumin (BSA) was investigated by fluorescence spectroscopy combined with UV-visible absorption and circular dichroism (CD) techniques under simulative physiological conditions for the first time. The quenching mechanism of fluorescence BSA by IPH was discussed. The binding parameters have been evaluated by fluorescence quenching method. The thermodynamic parameters, ΔH°, ΔS° and ΔG° calculated at different temperatures indicated that the hydrophobic force played a major role in the interaction of IPH to BSA. The distance, r between donor (BSA) and acceptor (IPH) was obtained according to the Förster's theory of non-radiation energy transfer and was found to be 2.21 nm. Experimental results showed that the α-helicity of BSA decreased from 66.4% (in free BSA) to 39.1% (in bound BSA). The effect of common ions on the binding constant was also investigated.     

Eu3+存在下盐酸头孢替安与牛血清白蛋白相互作用的研究

运用荧光光谱、紫外吸收光谱研究了Eu3+存在下盐酸头孢替安(Cefotiam Hydro-chloride,CH)与牛血清白蛋白(BSA)的相互作用.CH对BSA具有荧光猝灭作用,其猝灭机制为静态猝灭,BSA发射峰蓝移,二者之间的作用力主要为疏水作用和弱的静电作用.Eu3+的存在使得BSA发射峰蓝移程度降低,猝灭常数、结合常数、结合位点数减小,但没有改变CH对BSA的猝灭机制,热力学参数ΔH和ΔS都增大.从热力学参数的变化及Eu3+的竞争作用分析了Eu3+对CH与BSA作用影响的原因.     

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...     

变色酸与牛血清白蛋白的相互作用

采用荧光光谱法和紫外-可见分光光度法研究了变色酸与牛血清白蛋白之间的相互作用。结果表明:变色酸对牛血清白蛋白有较强的荧光猝灭作用。根据Stern-Volmer方程得到了荧光猝灭常数,并判断由于与变色酸反应而导致牛血清白蛋白的荧光猝灭属于静态猝灭。采用Lang-muir单分子吸附模型计算了结合常数和结合位点数。从计算得到的热力学参数ΔH和ΔS推断了变色酸与血清白蛋白反应的作用力为氢键和范德华力。     

速灭威与牛血清白蛋白作用的研究

在pH=7.4的生理条件下,应用荧光光谱法研究了速灭威与牛血清白蛋白间相互作用。结果表明:速灭威对牛血清白蛋白的荧光有较强的猝灭作用,测定不同温度下的猝灭常数,证实了速灭威对牛血清白蛋白的荧光猝灭过程机理为静态猝灭。根据猝灭结果计算了不同温度下的结合位点数、结合常数。应用同步荧光光谱法探讨了速灭威对牛血清白蛋白构象的影响。依据f ster非辐射能量转移理论确定受体间的结合距离和能量转移效率。     

Study of the interaction between 2,5-di-[2-(4-hydroxy-phenyl)ethylene]-terephthalonitril and bovine serum albumin by fluorescence spectroscopy

A new compound, 2,5-di-[2-(4-hydroxy-phenyl)ethylene]-terephthalonitrile (DHPEPN), was synthesized. The interaction between bovine serum albumin (BSA) and DHPEPN in Tris-HCl buffer solution (pH 7.4) was investigated using fluorescence and UV-vis absorption spectroscopy. The mechanism of BSA fluorescence quenched by DHPEPN is discussed according to the Stern-Volmer equation. The binding constant and the thermodynamic parameters ΔH, ΔS, ΔG at different temperatures were calculated. The results indicate that the van der Waals interaction and hydrogen bonding play major roles in the binding process. The distance between BSA and DHPEPN is estimated to be 3.59 nm based on the F?rster resonance energy transfer theory. The spectral changes of synchronous fluorescence and three-dimensional fluorescence suggest that both of the microenvironment of DHPEPN and the conformation of BSA are changed during binding between DHPEPN and BSA.     

Structural relationship and binding mechanisms of five flavonoids with bovine serum albumin

Flavonoids are structurally diverse and the most ubiquitous groups of dietary polyphenols distributed in various fruits and vegetables. In this study, the interaction between five flavonoids, namely formononetin-7-O-β-D-glucoside, calycosin- 7-O-β-D-glucoside, calycosin, rutin, and quercetin, and bovine serum albumin (BSA) was investigated by fluorescence and UV-vis absorbance spectroscopy. In the discussion, it was proved that the fluorescence quenching of BSA by flavonoids was a result of the formation of a flavonoid-BSA complex. Fluorescence quenching constants were determined using the Stern-Volmer and Lineweaver-Burk equations to provide a measure of the binding affinity between the flavonoids and BSA. The binding constants ranked in the order quercetin>rutin>calycosin>calycosin-7-O-β-D-glucoside ≈ formononetin-7-O-β-D-glucoside. The results of thermodynamic parameters ΔG, ΔH, and ΔS at different temperatures indicated that the hydrophobic interaction played a major role in flavonoid-BSA association. The distance r between BSA and acceptor flavonoids was also obtained according to F?rster's theory of non-radiative energy transfer.     

白杨素磺酸盐与牛血清白蛋白的相互作用

合成了白杨素磺酸钠和白杨素磺酸钙两种白杨素磺酸盐衍生物,并分别采用荧光光谱法研究了它们与牛血清白蛋白(BSA)的相互作用。结果表明:两种白杨素磺酸盐对BSA有较强的荧光猝灭作用,根据Stern-Volmer方程得到的荧光猝灭常数,可判断由于与白杨素磺酸盐反应而导致BSA的荧光猝灭均属于静态猝灭。采用位点结合模型公式和Frster非辐射能量转移理论计算了结合常数、结合位点数、结合距离。从计算得到的热力学参数焓变ΔH和熵变ΔS,推断了白杨素磺酸钠与BSA之间的作用力为静电引力,而白杨素磺酸钙与BSA之间的作用力为氢键和范德华力。并应用同步荧光技术研究了白杨素磺酸盐对BSA构象的影响。     

Study of the Binding of Herbacetin to Bovine Serum Albumin by Fluorescence Spectroscopy

In this paper, the interaction between herbacetin and BSA was investigated by fluorescence and three-dimensional fluorescence spectroscopy under simulated physiological conditions. It was proved that the fluorescence quenching of BSA by herbacetin was mainly the result of the formation of a herbacetin–BSA complex. The modified Stern–Volmer quenching constant and the corresponding thermodynamic parameters ΔH ⁰, ΔG ⁰ and ΔS ⁰ were calculated at different temperatures. The results indicated that electrostatic interactions were the predominant intermolecular forces in stabilizing the complex. The distance r=3.23 nm between the donor (BSA) and acceptor (herbacetin) was obtained according to Förster’s nonradioactive energy transfer theory. The synchronous fluorescence and three-dimensional fluorescence spectra results showed that the hydrophobity of amino acid residues increased in the presence of herbacetin. These results revealed that the microenvironment and conformation of BSA changed during the binding reaction.     

Interaction between Glyoxal-bis-(2-hydroxyanil) and Bovine Serum Albumin in Solution

The interaction between glyoxal-bis-(2-hydroxyanil) (GBH) and bovine serum albumin (BSA) was studied by spectroscopic methods including fluorescence spectroscopy, circular dichroism (CD) and UV–visible absorption spectra. The mechanism for quenching the fluorescence of BSA by GBH is discussed. The number of binding sites n and observed binding constant K _b were measured by the fluorescence quenching method. The thermodynamic parameters ΔH ^θ , ΔG ^θ , and ΔS ^θ were calculated at different temperatures and the results indicate that hydrogen bonding and van der Waals forces played major roles in the reaction. The distance r between the donor (BSA) and acceptor (GBH) molecules was obtained according to Förster’s theory of non-radiation energy transfer. Synchronous fluorescence and three-dimensional fluorescence spectra were used to investigate the structural change of BSA molecules that occur upon addition of GBH, and these results indicate that the secondary structure of BSA molecules is changed by the presence of GBH.     

Study on the Interaction Between Bovine Serum Albumin and Potassium Perfluoro Octane Sulfonate

The interactions between potassium perfluorooctanesulfonate (PFOS) and bovine serum albumin (BSA) were studied by fluorescence spectroscopy. The association constants between PFOS and BSA were obtained by fluorescence enhancing and fluorescence quenching respectively. Furthermore, fluorescence quenching was studied at different temperatures, and the binding constant was also determined by the method of fluorescence quenching. According to the thermodynamic parameters, the main binding force could be judged. The experimental results revealed that BSA and PFOS had strong interactions. The mechanism of quenching belonged to dynamic quenching and the main sort of binding force was hydrophobic force. IR-spectra proved the interaction changed the conformation of BSA.     

Interaction Between Ranitidine Hydrochloride and Bovine Serum Albumin in Aqueous Solution

The interaction between ranitidine hydrochloride (RAN) and bovine serum albumin (BSA) in aqueous solution was investigated by means of fluorescence, synchronous fluorescence, and UV-Vis spectroscopy. The fluorescence of BSA was quenched remarkably by RAN and the quenching mechanism was concluded to be static quenching. The binding constants K and the number of binding sites n were calculated at three different temperatures. The RAN–BSA binding distance was determined to be less than 8 nm, suggesting that energy transfer may occur from BSA to RAN. The interaction process is spontaneous. Based on the obtained thermodynamic parameters, electrostatic forces may play a major role in this process. In addition, the effect of RAN on the conformation of BSA was analyzed using synchronous fluorescence spectra.     

光谱法与分子模拟技术研究丽春红2R与牛血清蛋白的相互作用

采用荧光光谱、同步荧光光谱、紫外-可见吸收光谱及分子模拟技术研究了模拟生理条件下丽春红2R(P2R)与牛血清白蛋白(BSA)的相互作用。实验结果表明,P2R-BSA体系的荧光猝灭机制为内源荧光猝灭,猝灭原因为静态猝灭和非辐射能量转移;计算了不同温度下体系的结合常数Ka及结合位点数n;根据热力学参数推断出作用力类型;求出室温下荧光给体-受体间的结合距离;同步荧光法证实丽春红2R对BSA构象未产生影响;分子模拟研究结果表明二者间的主要作用力为氢键和疏水作用力。     

头孢拉定与血清白蛋白相互作用的光谱学研究

采用荧光和紫外吸收光谱法研究头孢拉定和牛血清白蛋白(BSA)的相互作用.研究发现,头孢柱定荧光猝灭牛血清白蛋白是由于形成了头孢拉定-牛血清白蛋白复合物.分别计算了不同温度下双分子猝灭常数kq和结合常数K.由热力学参数焓变(△H)、熵变(△S)和吉布斯自由能(△G),推断出头孢拉定与BSA的相互作用是一个疏水作用的自发过...     

Study on the interaction between thiazolopyrimidine analogues and bovine serum albumin

Fluorescence and ultraviolet spectroscopy were used to explore the interaction between thiazolopyrimidines (TAPM) and bovine serum albumin (BSA) under imitated physiological conditions. The experimental results show that thiazolopyrimidines can quench the fluorescence of BSA through a static quenching process. The binding constants, binding sites, and thermodynamic parameters at different temperatures were calculated. The calculated results indicate that the interaction between thiazolopyrimidines and BSA is driven mainly by Van der Waals' force and hydrogen bonds. The binding distances r was obtained based on F?rster theory of non-radiation energy transfer. The comparison of binding potency of thiazolopyrimidines and BSA suggests that the substituent on the benzene ring promotes the binding process of thiazolopyrimidines and BSA.     

Investigation of the Interaction Between Novel Spiro Thiazolo[3,2-a][1,3,5]Triazines and Bovine Serum Albumin by Spectroscopic Methods

The interaction between novel spiro thiazolo[3,2-a][1,3,5]triazines (NSTT) and bovine serum albumin (BSA) was investigated using fluorescence and ultraviolet spectroscopy at different temperatures (302 and 310 K) under imitated physiological conditions. The experimental results show that the fluorescence quenching mechanism between NSTT and BSA is by a static quenching mechanism. The binding constant (K _a) and number of binding sites (n) between NSTT and BSA at different temperatures were obtained. Negative values of ?G°, ?H°, and ?S° indicate that the interaction between NSTT and BSA is driven by hydrogen bonds and van der Waals forces. Using the Förster non-radiation energy transfer theory, the binding distance between BSA and NSTT was calculated. These results provide valuable information on the interaction between NSTT and BSA as well as the influence of substituent groups on the interaction.