黄腐酸与人血清白蛋白相互作用机制的光谱研究

利用荧光光谱研究了黄腐酸与HSA的相互作用,黄腐酸对HSA有明显的荧光猝灭作用,计算了黄腐酸与HSA作用的结合常数(Ka=1.2×107L/mol)、结合位点数(n=1.45)及结合距离(r0=2.92 nm)。黄腐酸与HSA的猝灭机制属于静态猝灭,并发生了分子内非辐射能量转移,能量从HSA向黄腐酸转移。同时,通过圆二色谱探讨了黄腐酸对HSA构象的影响,HSA与黄腐酸结合后引起了HSA肽链收缩,改变了HSA的二级结构,使HSA的结构变得更加紧密。     

烟碱与人血清蛋白相互作用的光谱研究

在0.1 mol/L的磷酸氢二钠-柠檬酸体系中,采用荧光光谱、紫外吸收光谱研究了人血清蛋白与烟碱的相互作用.荧光滴定表明这种相互作用使HSA的内源荧光猝灭.通过猝灭常数、结合常数和结合位点数的计算,证明了这种猝灭为静态猝灭机制.尼古丁和HSA形成11稳定复合物;考察不同温度和酸度下的猝灭作用,进一步证实其静态猝灭行为和疏水作用机制.紫外吸收光谱和同步荧光光谱表明,相互作用引起HSA构象变化,而同步荧光光谱提示结合位点更接近于色氨酸.     

杜鹃素新结构衍生物与人血清白蛋白相互作用的光谱及分子对接

采用光谱法及分子对接法考察了该化合物与人血清白蛋白(HSA)的相互作用。荧光光谱分析表明,DJS-NO_2对HSA的荧光有明显的猝灭作用,其机制属于静态荧光猝灭;温度为25℃和37℃时,猝灭常数分别为6.691×10~(13)mol/(L·s)和3.433×10~(13)mol/(L·s);结合常数分别为4.914×10~5mol/L和4.610×10~5mol/L,具有一个结合位点。热力学分析表明,该化合物与HSA之间的结合以疏水作用力为主;三维荧光光谱分析表明DJS-NO_2导致HSA氨基酸残基微环境和二级构象发生变化。圆二色谱分析显示二者的结合使得HSA的α-螺旋含量减少,提示HSA构象发生变化。分子模拟结果显示DJS-NO_2主要与HSA的位点I结合,且该化合物通过氢键与ALA118结合最紧密。     

荧光法研究金属离子对橙皮素与牛血清白蛋白相互作用的影响

采用荧光光谱和三维荧光光谱法研究了橙皮素(HSP)与牛血清白蛋白(BSA)之间的相互作用,并考察了共存金属离子Cu2+,Zn2+对二者相互作用的影响。实验结果表明,HSP对BSA的内源性荧光具有猝灭作用,猝灭类型为静态猝灭,作用力类型是氢键和范德华力,Cu2+,Zn2+的加入未改变HSP对BSA的猝灭类型和作用力类型。通过比较猝灭常数、结合常数、结合位点数、猝灭效率和三维荧光光谱图变化,推知Cu2+,Zn2+能与BSA产生结合作用,使其成为受制状态下的刚性肽链,从而影响HSP进入BSA疏水腔,减弱了HSP与BSA的结合能力,表现为与HSP存在竞争作用。     

多柔比星稀土配合物与人血清白蛋白相互作用的研究

运用荧光光谱法研究了多柔比星稀土配合物(ADM-M)与人血清白蛋白(HSA)的相互作用.结果表明:多柔比星稀土配合物对HSA的荧光有较强的猝灭作用,其荧光猝灭为混合猝灭过程.求得多柔比星稀土配合物与HSA的结合常数、结合位点数.由热力学参数确定了多柔比星稀土配合物与HSA的作用力类型.同时用同步荧光光谱法考察了多柔比星...     

水杨酸与人血清白蛋白的相互作用研究

采用荧光光谱法,紫外光谱法及圆二色谱法研究了具抗凝血作用的水杨酸与人血清白蛋白(HSA)的相互作用.结果表明,水杨酸对人血清白蛋白荧光产生猝灭现象,猝灭方式为静态猝灭.通过同步荧光法和圆二色谱法发现水杨酸的存在明显改变人血清白蛋白的构象.     

天竺葵素与人血清白蛋白相互作用的光谱学研究

采用荧光光谱、紫外吸收光谱和同步荧光光谱法研究了天竺葵素与人血清蛋白(HSA)的相互作用.结果表明:天竺葵素能使HSA发生内源荧光猝灭,属静态猝灭机理.25、30和37℃下,天竺葵素与HSA的静态猝灭速率常数分别为3.357×104,4.288×104和4.851×104L·mol-1,结合常数分别为3.24×104、...     

2-(4-甲基苯基)-3-(N-乙酰基)-5-(2-羟基苯基)-1,3,4-噁唑啉的合成及与人血清白蛋白的相互作用

合成了2-(4-甲基苯基)-3-(N-乙酰基)-5-(2-羟基苯基)-1,3,4-噁唑啉(MPAHO),并用核磁共振波谱法和红外光谱法对其进行了表征。采用荧光光谱技术研究了MPAHO与人血清白蛋白(HSA)的相互作用。结果表明:MPAHO对HSA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MPAHO反应而导致HSA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MPAHO与HSA之间的作用力为静电引力。并应用同步荧光光谱和三维荧光技术研究了MPAHO对HSA构象的影响。     

3-溴丙酮酸与人血清白蛋白相互作用的光谱学研究

运用荧光光谱、紫外可见吸收光谱和圆二色光谱法研究了抗肿瘤药物3-溴丙酮酸(3-Bromopyruvic acid,3-BrPA)与人血清白蛋白(Human serum albumin,HSA)的相互作用.3-BrPA对HSA的猝灭机制属于静态猝灭,并发生分子间非辐射能量转移.热力学数据显示,二者之间的作用力主要为静电作用;同步荧光光谱表明,3-BrPA与蛋白质中接近色氨酸残基的区域发生了相互作用;荧光光谱研究发现,Zn2+存在时3-BrPA对HSA的猝灭程度进一步增强;圆二色光谱法研究蛋白二级结构结果显示,3-BrPA对HSA的结构影响非常小.     

具抗凝血作用的三种钕配合物与人血清白蛋白的相互作用

采用荧光光谱法,紫外光谱法以及圆二色谱法研究了具抗凝血作用的水杨酸钕((NdL′3.2H2O,L′=水杨酸离子))、华法灵钕(NdL3.2H2O,L=华法灵离子)和华法灵水杨酸钕(NdL2L′.2H2O)3种配合物与人血清白蛋白的相互作用。结果表明:配合物对人血清白蛋白(HSA)的荧光产生猝灭现象;配合物的存在使得HSA紫外吸收光谱的强度增加;配合物的存在也对HSA的构象产生影响。水杨酸钕的猝灭方式为动态与静态猝灭,而华法灵钕和华法灵水杨酸钕的猝灭方式属于两者之间生成了不发荧光的复合物而导致的静态猝灭。并分别确定了它们的结合力类型:华法灵钕与HSA之间主要作用力是静电作用力;水杨酸钕与HSA之间主要作用力为典型的疏水作用力;华法灵水杨酸钕与HSA之间为氢键和范德华力。计算了配合物与人血清白蛋白的结合常数K和结合位点数n。     

Spectrometric Study on the Interaction of Indocyanine Green with Human Serum Albumin

The interaction of indocyanine green(ICG) with human serum albumin(HSA) was investigated via various spectrometric(UV-visible, fluorescence and circular dichroism) techniques. The experimental results indicate that the interaction of ICG with HSA depends on the values of R(R is defined as the molar ratio of HSA to ICG). The interaction of ICG with HSA can form two complexes with intrinsic binding constants(K_a) of 2.97×10⁵(R≤2) and 2.63×10⁴(R>2), respectively. The fluorescence and induced CD(ICD) spectra of ICG demonstrate that binding the first mole of HSA to ICG can form a chiral ICG-HSA complex with strong fluorescence emission, and the chirality and fluorescence of ICG-HSA complex can be significantly reduced by adding another mole of HSA to ICG. Furthermore, although both ICG and ICG-HSA complexes followed an energy-dependent endocytosis process to enter living cells, the cellular uptaken dynamic mechanism of ICG was significantly affected by the HSA conjugation.     

Studies of the Interaction Between Ronidazole and Human Serum Albumin by Spectroscopic and Molecular Docking Methods

Ronidazole (RNZ) is widely used for the therapeutic treatment of farmed animals and is suspected of being a human carcinogen and mutagen. The interaction between RNZ and human serum albumin (HSA) was investigated systematically by fluorescence spectroscopy, synchronous fluorescence, three-dimensional fluorescence, CD spectroscopy, UV–vis absorption spectroscopy and a molecular docking study. The results indicate that the probable quenching mechanism of HSA by RNZ is dynamic quenching. The corresponding thermodynamic parameters, such as ΔH, ΔS and ΔG, etc., were calculated according to the van’t Hoff equation. The results indicate that the forces acting between RNZ and HSA are mainly hydrogen bonds and van der Waals forces. The conformational changes in the interaction were studied by synchronous fluorescence, CD spectroscopy and three-dimensional fluorescence spectra. The results reveal that the microenvironment and conformation of HSA has been changed. A molecular modeling study further confirmed the binding mode obtained by the experimental studies.     

Investigation of the binding of Salvianolic acid B to human serum albumin and the effect of metal ions on the binding

The studies on the interaction between HSA and drugs have been an interesting research field in life science, chemistry and clinical medicine. There are also many metal ions present in blood plasma, thus the research about the effect of metal ions on the interaction between drugs and plasma proteins is crucial. In this study, the interaction of Salvianolic acid B (Sal B) with human serum albumin (HSA) was investigated by the steady-state, synchronous fluorescence and circular dichroism (CD) spectroscopies. The results showed that Sal B had a strong ability to quench the intrinsic fluorescence of HSA through a static quenching mechanism. Binding parameters calculated showed that Sal B was bound to HSA with the binding affinities of 10(5) L mol(-1). The thermodynamic parameters studies revealed that the binding was characterized by positive enthalpy and positive entropy changes, and hydrophobic interactions were the predominant intermolecular forces to stabilize the complex. The specific binding distance r (2.93 nm) between donor (HSA) and acceptor (Sal B) was obtained according to F?rster non-radiative resonance energy transfer theory. The synchronous fluorescence experiment revealed that Sal B cannot lead to the microenvironmental changes around the Tyr and Trp residues of HSA, and the binding site of Sal B on HSA is located in hydrophobic cavity of subdomain IIA. The CD spectroscopy indicated the secondary structure of HSA is not changed in the presence of Sal B. Furthermore, The effect of metal ions (e.g. Zn(2+), Cu(2+), Co(2+), Ni(2+), Fe(3+)) on the binding constant of Sal B-HSA complex was also discussed.     

Investigation of nitroxoline-human serum albumin interactions by spectroscopic methods

Nitroxoline is a wide spectrum antibacterial and is one of the most important urinary antiseptics.The interaction between nitroxoline and human serum albumin(HSA)has been investigated systematically by fluorescence spectroscopy,synchronous fluorescence,three-dimensional fluorescence,CD spectroscopy and UV-Vis absorption spectroscopy.The results indicated that the quenching of HSA by nitroxoline was static.The corresponding thermodynamic parameters △H,△S and △G calculated according to van’t Hoff equation revealed that the intermolecular forces acting between nitroxoline and HSA were mainly hydrogen bonding and van der Waals forces.The conformational changes in the interaction were studied by synchronous fluorescence,CD spectroscopy and three-dimensional fluorescence spectra which showed changes in the microenvironment and conformation of HSA.     

Binding of Dioxopromethazine Hydrochloride with Human Serum Albumin and Its Effect on the Conformation of the Protein

The interaction between dioxopromethazine hydrochloride (DPZ) and human serum albumin (HSA), in vitro, was investigated by means of fluorescence, absorption and circular dichroism (CD) spectroscopy. The results obtained from analysis of the fluorescence spectra indicate that DPZ has a strong ability to quench the intrinsic fluorescence of HSA through a static quenching mechanism. The HSA?CDPZ binding distance was determined to be less than 7?nm, suggesting that energy transfer from HSA to DPZ may occur. The thermodynamic parameters of the interaction between DPZ and HSA were measured according to the van??t Hoff equation. The negative enthalpy change (??H ⁰) and positive entropy change (??S ⁰) values indicate that hydrophobic and electrostatic interactions play major roles in the binding between DPZ and HSA. The binding process was a favorable process in which the Gibbs energy change (??G ⁰) is negative. The results of displacement experiments suggested that DPZ is located in site I of HSA within subdomain IIA. In addition, the results of absorption, synchronous fluorescence and CD spectra show that binding of DPZ with HSA can induce conformational changes in HSA.     

白藜芦醇类似物与人血清白蛋白的相互作用

采用荧光光谱、三维荧光光谱、紫外吸收光谱研究白藜芦醇类似物(Z)-2-(3,4-二甲氧苯基)-3-(4-二甲氨基苯基)丙烯腈(HCQ)与人血清白蛋白(HSA)的相互作用,探讨其作为抗肿瘤药物的可能。结果发现HCQ与HSA形成了基态配合物,HCQ主要结合于HSA的位点Ⅰ,与位点Ⅱ也有微量的结合,反应为自发的放热反应,其ΔH、ΔS、ΔG均小于零,二者之间的结合力为氢键或者范德华力,结合常数为104～105数量级。HCQ与HSA的结合使HSA构象发生变化,Trp-214所处的环境疏水性增加,使得其内源性荧光显著降低。说明合成的白藜芦醇类似物能够与人血清白蛋白结合。     

Human serum albumin binding studies of a new platinum(IV) complex containing the drug pregabalin: experimental and computational methods

A new platinum(IV) complex, [Pt(en)(Cl)₂(Pregabalin)₂], containing the drug pregabalin was synthesized and characterized by elemental analysis, FT-IR, ¹H NMR, mass spectrum, thermogravimetric analysis (TGA), molecular docking and RHF/PM6 method. Also, the interaction of Pt(IV) complex with human serum albumin (HSA) was studied by using UV–vis, fluorometric, circular dichroism (CD) spectroscopies and molecular docking techniques. The results demonstrated that the binding of the complex to HSA caused strong fluorescence quenching of HSA through static quenching mechanism. Hydrogen bonds and van der Waals contacts are the major forces in the stability of protein-Pt(IV) complex and the process of the binding of complex with HSA was enthalpy driven (ΔH = –105.8?kJ·mol^?1). The results of CD and UV–vis spectroscopy indicated that the binding of the complex to HSA caused conformational changes in HSA. In addition, the study of molecular docking and RHF/PM6 method confirm the experimental results with respect to the mechanism of binding.     

In vitro study on the interaction between thiophanate methyl and human serum albumin

Thiophanate methyl (MT) is one of the widely used fungicides to control important fungal diseases of crops, which has led to potential toxicological risk to public health. Several different transport proteins exist in blood plasma, but albumin only is bound by a wide diversity of xenobiotics reversibly with high affinity. We studied the interaction of MT with human serum albumin by using spectroscopic methods including fluorescence quenching technology, UV and Fourier transform infrared (FT-IR) spectroscopy under simulative physiological conditions. The result of fluorescence titration revealed that MT could quench the intrinsic fluorescence of HSA. The binding process was exothermic and spontaneous, as indicated by the thermodynamic analyses. In addition, the studies of FT-IR spectroscopy showed that the binding of MT to HSA changed molecular conformation of HSA. The results obtained from molecular modeling showed that the interaction between MT and HSA was dominated by hydrophobic force, and there was also hydrogen bond interaction between the pesticide and the residues of HSA, which was in good agreement with the result of binding mode.     

Studies on interaction between gatifloxacin and human serum albumin as well as effect of copper(II) on the reaction

The binding characteristics of gatifloxacin (GTFX) and human serum albumin (HSA) have been studied by fluorescence spectroscopy in aqueous solution, and the interaction influenced by copper(II) was also explored in the paper. The results show that the two-reaction equilibrium constant and the number of binding sites were K = 1.16 x 10(5) l mol(-1), n = 1.27 for GTFX and K = 1.62 x 10(5) l mol(-1), n = 1.74 for GTFX-Cu2+, respectively. The quenching mechanism of fluorescence of HSA by GTFX is a static quenching procedure. The binding distance between GTFX and HSA and the energy transfer efficiency are obtained based on the theory of Fōrster spectroscopy energy transfer. The effect of GTFX on the conformation of HSA was also been analyzed by using synchronous fluorescence spectroscopy. The interaction of GTFX and HSA has been studied by flow-mixed microcalorimetry in the absence and presence of copper(II) and their thermodynamic parameters were obtained. The enthalpy changes and the entropy changes were calculated to be DeltaH approximately 0, DeltaS > 0 in the absence of copper(II),which indicated that static forces played major role in the interaction of GTFX and HSA, and to be DeltaH approximately 0, DeltaS > 0 in the presence of copper(II),which indicated that the static forces also played major role on the reaction. The molar free energy changes of the two reactions are identical with each other because the entropy-enthalpy compensation happened between the two reactions.     

补骨脂素和异补骨脂素键合人血清白蛋白的比较

将互为同分异构体的两种植物药活性组分补骨脂素和异补骨脂素作为研究对象,利用荧光光谱、紫外光谱、圆二色谱及傅立叶变换红外光谱详细比较研究了这两种香豆素类化合物与人血清白蛋白(HSA)的键合作用.不同光谱的结果定性、定量地显示了HSA二级结构变化的程度.依据荧光滴定实验及Van′t Hoff公式求出了反应的热力学参数(ΔH和ΔS)的值.根据修正后的Stern-Volmer和Scatchard方程和荧光光谱数据分别求得不同温度(296,303,310及318 K)下药物与蛋白相互作用的结合常数及结合位点数;且根据F觟rster偶极-偶极能量转移理论,求得药物与HSA间的键合距离;利用竞争实验确定了药物在HSA上的键合位点为site II.从分子水平上揭示了这两种化合物与HSA相互作用的机制.