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1.
The interaction between aglycon of daunorubicin (DNR-A) and human serum albumin (HSA) was investigated using fluorescence quenching and modeling. Results shown that fluorescence quenching of HSA by DNR-A resulted from the formation of DNR-A-HSA complex. The quenching constants were determined via measurement of the binding affinity between DNR-A and HSA using the Stern-Volmer equation. The thermodynamic parameters DeltaG, DeltaH, DeltaS and the binding distance r were calculated. Furthermore, SFS and UV spectra suggested that the complex changed the conformation of HSA and that hydrophobic interactions played a major role in DNR-A-HSA association, which was in good agreement with the results of the modeling study. Moreover, the SFS technique was successfully applied to determine the total proteins in biology samples with satisfactory results. 相似文献
2.
In recent years, bezafibrate (BZF) has been frequently detected in environmental media. In order to reveal the toxicity of such an emerging pollutant, its interaction with human serum albumin (HSA) was studied by fluorescence spectrometry, circular dichroism, and equilibrium dialysis. Fluorescence data showed that the fluorescence quenching of HSA by BZF resulted from the formation of HSA-BZF complex. The binding constants were determined to be 3.33 × 103, 2.84 × 103 M?1 at 298 and 309.5 K, respectively. The thermodynamic determination indicated that the hydrophobic and electrostatic interaction were the dominant binding force. The conformational investigation showed that the presence of BZF increased the α-helix content of HSA and induced the slight unfolding of the polypeptides of protein. Finally, the equilibrium dialysis showed that 0.56 mM BZF decreased the binding of vitamin B? to HSA by 29%. 相似文献
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4.
Binding of glycyrrhizin to human serum and human serum albumin 总被引:3,自引:0,他引:3
S Ishida Y Sakiya T Ichikawa M Kinoshita S Awazu 《Chemical & pharmaceutical bulletin》1989,37(1):226-228
The binding of glycyrrhizin (GLZ) to human serum and human serum albumin (HSA) was examined by an ultrafiltration technique. Specific and nonspecific bindings were observed in both human serum and HSA. The association constants (K) for the specific bindings were very similar: 1.31 x 10(5) M-1 in human serum and 3.87 x 10(5) M-1 in HSA. The number of binding sites (n) and the linear binding coefficient (phi) in HSA were 1.95 and 3.09 x 10(3) M-1, respectively. When the human serum protein concentration was assumed to be 4.2% (equal to the measured serum albumin concentration), n in human serum was 3.09, which is similar to the n value in HSA, and phi in human serum was 0.71 x 10(3) M-1, which is reasonably close to that for HSA. The binding pattern of GLZ with human serum protein on Sephadex G-200 column chromatography showed that GLZ binds to only the albumin fraction. It was concluded that the GLZ-binding sites in human serum exist mainly on albumin and GLZ binds to specific and nonspecific binding sites at lower and higher concentrations than approximately 2 mM, respectively. 相似文献
5.
Fengling Cui Junli Wang Yanrui Cui Jianping Li Yan Lu Jing Fan Xiaojun Yao 《Analytical sciences》2007,23(6):719-725
The binding of N-(p-ethoxy-phenyl)-N'-(1-naphthyl)thiourea (EPNT) to human serum albumin (HSA) was investigated under simulative physiological conditions by fluorescence spectra in combination with UV absorption spectroscopy and a molecular modeling method. A strong fluorescence quenching reaction of EPNT to HSA was observed, and the quenching mechanism was suggested to be static quenching according to the Stern-Volmer equation. The binding constants (K) at different temperatures as well as thermodynamic parameters, enthalpy change (DeltaH) and entropy change (DeltaS), were calculated according to relevant fluorescent data and the vant' Hoff equation. This indicated that a hydrophobic interaction was a predominant intermolecular force for stabilizing the complex, which is in agreement with the results of molecule modeling study. The effects of energy transfer and other ions on the binding constant were considered. In addition, synchronous fluorescence technology was successfully applied to the determination of HSA added into the EPNT solution. 相似文献
6.
I. M. Vlasova A. M. Saletskii 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2010,84(6):1065-1070
The effective constants of binding for probes of the fluorescein family (fluorescein and its halogen derivatives, eosin and
erythrosin) with human serum albumin (HSA) at different pH were determined. It was found that the introduction of halogen
groups into the structural formula of fluorescein changes the character of the dependence on pH of the effective constant
of binding of a nanomarker with HSA: the nonlinear dependence of the effective constants of binding with its protein typical
for fluorescein, eosin, and erythrosine is characterized by an almost linear reduction with increasing pH dependence of the
effective constants of their binding with human serum albumin. It was shown that the presence of more electronegative atoms
in the structural formula of nanomarker leads to decrease of values of effective constants of nanomarker binding with HSA. 相似文献
7.
The interactions between fluoroquinolones and human serum albumin (HSA) were investigated by affinity capillary electrophoresis (ACE) and fluorescence quenching technique. Based on the efficient separation of several fluoroquinolones using a simple phosphate buffer, the binding constants of fluoroquinolones with HSA were determined simultaneously during one set of electrophoresis by ACE method. The thermodynamic parameters were obtained from data at different temperatures, and the negative ΔH and ΔS values showed that both hydrogen bonds and van der Waals interaction played major roles in the binding of fluoroquinolones to HSA. The interactions were also studied by fluorescence quenching technique. The results of fluorescence titration revealed that fluoroquinolones had the strong ability to quenching the intrinsic fluorescence of HSA through the static quenching procedure. The binding site number n, apparent binding constant Kb and the Stern-Volmer quenching constant Ksv were determined. The thermodynamic parameters were also studied by fluorescence method, and the results were consonant with that of ACE. 相似文献
8.
Interaction of tetrandrine with human serum albumin: a fluorescence quenching study. 总被引:4,自引:0,他引:4
Chun Wang Qiu-Hua Wu Cai-Rui Li Zhi Wang Jing-Jun Ma Xiao-Huan Zang Na-Xin Qin 《Analytical sciences》2007,23(4):429-433
The interaction of tetrandrine with human serum albumin (HSA) was studied by measuring fluorescence quenching spectra, synchronous fluorescence spectra and ultra-violet spectra. The fluorescence quenching spectra of HSA in the presence of tetrandrine showed that tetrandrine quenched the fluorescence of HSA. The quenching constants of tetrandrine on HSA were determined using the Stern-Volmer equation. Static quenching and non-radiation energy transfer were the two main reasons leading to the fluorescence quenching of HSA by tetrandrine. According to the F?rster theory of non-radiation energy transfer, the binding distances (r) and the binding constants (K(A)) were obtained. The thermodynamic parameters obtained in this study revealed that the interaction between tetrandrine and HSA was mainly driven by a hydrophobic force. The conformational changes of HSA were investigated by synchronous spectrum studies. 相似文献
9.
荧光法研究氢氯噻嗪与人血清白蛋白的相互作用 总被引:21,自引:0,他引:21
采用荧光光度法研究了不同酸度下,降压利尿药氢氯噻嗪(Hydrochlomthiazide)与人血清白蛋白(HSA)间的相互作用。求得不同酸度下药物与人血清白蛋白相互作用的形成常数,讨论了微量金属离子对药物与血清白蛋白形成常数的影响,并根据热力学常数确定了该药物与血清白蛋白之间的作用力类型,在此基础上依据福斯特Foerster非辐射能量转移机理探讨了氢氯噻嗪与人血清白蛋白相互结合时其给体-受体间的距离和能量转移效率。从而证实了氢氯噻嗪与人血清白蛋白结合作用为静态猝灭过程,且阐明了其猝灭机制是通过能量转移产生的。 相似文献
10.
Summary The interaction thermodynamics of heptacarboxylporphyrin (HCP) and protoporhyrin (PP) with human serum albumin (HSA) was studied
by affinity capillary electrophoresis (ACE) over the temperature range of 25–50°C, where HCP and PP bound to HSAvia 1:1 molecular association. The binding equilibrium constants (pH 7.4, phosphate buffer) for the binding of HCP with HSA were
found to decrease with an increase in temperature, whereas the binding constants of the PP/HSA system appeared to be independent
of temperature changes over the range studied. The van’t Hoff relationship (25–50°C) was found to be linear for the interaction
of either HCP or PP with HSA. However, the interaction thermodynamics for both of these porphyrins with HSA were found to
be quite different. In particular, the interaction of HCP (a hydrophilic porphyrin) with HSA appeared to be based on an enthalpy-driven
process, whereas the binding between PP (a hydrophobic porphyrin) and HSA driven by a favorable change in entropy. The ability
of using ACE to evaluate the interaction thermodynamics of serum proteins (e.g., HSA) with ligands (e.g., porphyrins and related
compounds) should aid in the development of new and more effective photosensitizers in the photodynamic therapy of cancer. 相似文献
11.
Based on the chiral separation of several basie drugs, dimetindene, tetryzoline, theodrenaline and verapamil, the liquid pre-colunm capillary electrophoresis (LPC-CE) technique was established. It was used to determine free concentrations of drug enantiomers in mixed solutions with human serum albumin (HSA). To prevent HSA entering the CE chiral separation zone, the mobility differences between HSA and drugs under a specific pH condition were employed in the LPC. Thus, the detection confusion caused by protein was totally avoided. Further study of binding constants determination and protein binding competitions was carried out. The study proves that the LPC technique could be used for complex media, particularly the matrix of protein coexisting with a variety of drugs. 相似文献
12.
The magnesium and calcium binding on human serum albumin (HSA) was studied using an affinity chromatography approach. The effects of the mobile phase pH, its ionic strength and column temperature on the transfer equilibrium constants were studied. The thermodynamic data corresponding to the electrostatic interactions occurring during the HSA-ion binding were determined. Enthalpy-entropy compensation revealed that the ion binding mechanism at HSA was independent of the ionic strength, the same at four pH values (6.5, 8, 8.5 and 9), but presented a weak change at physiological pH around 7-7.5 due to a HSA phase transition. A theoretical model based on the Gouy-Chapman theory allows to determine the relative charge density of the HSA surface implied in the binding process and the variation of the number of ions bound to one albumin molecule with the pH. 相似文献
13.
Cheng FQ Wang YP Li ZP Dong C 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,65(5):1144-1147
The binding of bromsulphalein (BSP) with human serum albumin was investigated at different temperatures, 298 and 308 K, by the fluorescence spectroscopy at pH 7.24. The binding constant was determined by Stern-Volmer equation based on the quenching of the fluorescence HSA in the presence of bromsulphalein. The effect of various metal ions on the binding constants of BSP with HSA was investigated. The thermodynamic parameters were calculated according to the dependence of enthalpy change on the temperature as follows: DeltaH and DeltaS possess small negative (9.3 kJ mol(-1)) and positive values (22.3 J K(-l)mol(-l)), respectively. The experimental results revealed that BSP has a strong ability to quench the intrinsic fluorescence of HSA through a static quenching procedure. The binding constants between BSP to HSA were remarkable and independent on temperature. The binding constants between HSA and BSP decreased in the presence of various ions, commonly decreased by 30-55%. The hydrophobic force played a major role in the interaction of BSP with HSA. All these experimental results and theoretical data clarified that BSP could bind to HSA and be effectively transported and eliminated in body, which could be a useful guideline for further drug design. 相似文献
14.
利用荧光光谱和同步荧光光谱研究了不同温度下苯胺蓝黑与人血清白蛋白相互作用时的荧光猝灭及构象的变化情况。实验结果表明,苯胺蓝黑与人血清白蛋白之间可以发生相互作用,而且有较强的结合。同步荧光光谱研究了人血清白蛋白与苯胺蓝黑的相互作用中人血清白蛋白构象的变化,结果显示二者结合改变了蛋白质的微环境。热力学参数说明小分子与蛋白质的作用以疏水作用为主。 相似文献
15.
The binding mechanism of molecular interaction between 5-(ethoxycarbonyl)-6-methyl-4-phenyl-3,4-dihydropyrimidin-2(1H)-one (a dihydropyrimidinones derivative, EMPD) and human serum albumin (HSA) was studied using spectroscopic methods and modeling technique. The quenching mechanism was investigated in terms of the binding constants and the basic thermodynamic parameters. The results of spectroscopic measurements suggested that EMPD have a strong ability to quench the intrinsic fluorescence of HSA through static quenching procedure. The drug-protein complex was stabilized by hydrophobic forces and hydrogen bonding as indicated from the thermodynamic parameters and synchronous fluorescence spectra, which was consistent with the results of molecular docking and accessible surface area calculation. Competitive experiments indicated that a displacement of warfarin by EMPD, which revealed that the binding site of EMPD to HSA was located at the subdomains IIA. The distance between the donor and the acceptor was 4.85nm as estimated according to F?rster's theory of non-radiation energy transfer. The effect of metal ions on the binding constants was also investigated. The results indicated that the binding constants between EMPD and HSA increased in the presence of common metal ions. 相似文献
16.
A novel type of 2-(un)substituted phenyl-2,3-dihydroquinazolin-4(1H)-one (DQL) derivatives were designed and synthesized to study the impact of halogen substituents on interactions between DQL and human serum albumin (HSA) by comparison methodology. The interactions between DQL and HSA were studied by fluorescence spectroscopy. The intrinsic fluorescence of human serum albumin was quenched by DQL through a static quenching mechanism. Site marker competitive experiments showed that DQL bound to HSA in site II (subdomain IIIA). The binding constants, the numbers of binding sites and the thermodynamic parameters were measured too. The results indicated that the interactions were spontaneous, mainly through hydrophobic forces, and the substitution by halogen atoms in the benzene ring could increase the interactions between DQL and HSA. Furthermore, the binding affinity was enhanced gradually with the increasing of halogen atomic number. 相似文献
17.
The interactions between terazosin and bovine serum albumin (BSA) were studied by spectrofluorimetry. The binding constants of terazosin with BSA were measured at different temperatures. The effects of various metal ions on the binding constants of terazosin with BSA were also studied. The optimum conditions of synchronous fluorometric determination of terazosin were studied and the method was successfully applied to the determination of terazosin added to serum and urine samples (3σ detection limit 0.21 mg l−1). 相似文献
18.
Epimerization and racemization of carbenicillin, ethiazide, etoposide and oxazepam acetate were examined kinetically in the presence of human serum albumin (HSA). The concentration of both optical isomers of each drug was determined by stereospecific high-performance liquid chromatography. The apparent rate constants of epimerization or racemization and hydrolysis were estimated from the concentration-time data. HSA retarded the racemization of ethiazide and the epimerization of etoposide. The binding of the drugs to HSA may inhibit the attack of hydroxy ion and/or water molecule and thus retard the epimerization and the racemization. HSA accelerated the epimerization of carbenicillin, which is charged at the pH studied. Ion-ion and ion-dipole interactions between carbenicillin and HSA activate the carbenicillin molecule favorable for the attack of hydroxy ion and/or water molecule. The hydrolysis rates of ethiazide, carbenicillin and oxazepam acetate were increased by the addition of HSA. The hydrolysis rate of d-oxazepam acetate enantiomer bound to HSA was twice that of the l-enantiomer, which suggests that the esterase-like activity of HSA is enantioselective. Differences in the binding affinities of the drug's enantiomers to HSA may account for the selectivity. 相似文献
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M. S. Jovanovic B. Zmbova D. Zivanov-Stakic S. Vladimirov 《Journal of Radioanalytical and Nuclear Chemistry》1993,171(2):451-456
The interaction of bilirubin and99mTc-HIDA and99mTc-IODIDA has been studied in rats. The mechanism of this interaction has been examined at the level of binding with human serum albumin (HSA) by the in vitro method. Percentage of binding with HSA, and affinity constants for99mTc-IODIDA were determined with and without bilirubin. Bilirubin was labeled with99mTc and its interaction with HSA was also examined. 相似文献