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1.
The interaction between apigenin (Ap) and bovine serum albumin (BSA) in physiological buffer (pH = 7.4) is investigated by
fluorescence quenching technique and UV-vis absorption spectra. The results reveal that Ap could strongly quench the intrinsic
fluorescence of BSA. The quenching mechanism of Ap for BSA varies with the change of Ap concentration. when Ap concentration
is lower, it is a static quenching procedure, when Ap concentration is higher, a combined quenching (both static and dynamic)
would operate. The apparent binding constants Ka and number of binding sites n of Ap with BSA are obtained by fluorescence
quenching method. The thermodynamic parameters, enthalpy change (Δr
H
m
and entropy change (Δr
S
m
), are calculated to be −15.382 kJ mol−1 K−1 < 0 and 104.888 J mol−1 K−1 > 0, respectively, which indicate that the interaction of Ap with BSA is driven mainly by hydrogen bonding and hydrophobic
interactions. The distance r between BSA and Ap is calculated to be 1.89 nm based on F?rster’s non-radiative energy transfer theory. The results of synchronous
fluorescence spectra show that binding of Ap with BSA cannot induce conformational changes in BSA. 相似文献
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Liu R Yu X Gao W Ji D Yang F Li X Chen J Tao H Huang H Yi P 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(5):1535-1539
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. 相似文献
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The interaction of a flavonoid molecule (puerarin) with bovine serum albumin (BSA) was characterized by isothermal titration
calorimetry (ITC), optical spectroscopic technique, and molecular modeling method under physiological conditions. The binding
parameters for the reaction were calculated according to ITC experiments at different temperatures. The thermodynamic parameters,
negative enthalpy changes (ΔH), and positive entropy (ΔS) indicated that the binding processes were entropically driven. The alterations of protein secondary structure in the presence
of puerarin in aqueous solution were estimated by the evidences from FT-IR and CD spectroscopy with reductions of α-helices.
On the basis of fluorescence resonance energy transfer (FRET) between excited tryptophan in BSA and BSA bound puerarin, the
critical transfer distance and mean distance between tryptophan in BSA and puerarin were estimated. 相似文献
4.
Zhang G Wang L Fu P Hu M 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,82(1):424-431
The mechanism and conformational changes of farrerol binding to bovine serum albumin (BSA) were studied by spectroscopic methods including fluorescence quenching technique, UV–vis absorption, circular dichroism (CD) spectroscopy and Fourier transform infrared (FT-IR) spectroscopy under simulative physiological conditions. The results of fluorescence titration revealed that farrerol could strongly quench the intrinsic fluorescence of BSA through a static quenching procedure. The thermodynamic parameters enthalpy change and entropy change for the binding were calculated to be −29.92 kJ mol−1 and 5.06 J mol−1 K−1 according to the van’t Hoff equation, which suggested that the both hydrophobic interactions and hydrogen bonds play major role in the binding of farrerol to BSA. The binding distance r deduced from the efficiency of energy transfer was 3.11 nm for farrerol–BSA system. The displacement experiments of site markers and the results of fluorescence anisotropy showed that warfarin and farrerol shared a common binding site I corresponding to the subdomain IIA of BSA. Furthermore, the studies of synchronous fluorescence, CD and FT-IR spectroscopy showed that the binding of farrerol to BSA induced conformational changes in BSA. 相似文献
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Yu X Lu S Yang Y Li X Yi P 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,83(1):609-613
The fluorescence and ultraviolet spectroscopies were explored to study the interaction between N-confused porphyrins-edaravone diad (NCP-EDA) and bovine serum albumin (BSA) under simulative physiological condition at different temperatures. The experimental results show that the fluorescence quenching mechanism between NCP-EDA and BSA is a combined quenching (dynamic and static quenching). The binding constants, binding sites and the corresponding thermodynamic parameters (ΔG, ΔH, and ΔS) of the interaction system were calculated at different temperatures. According to F?rster non-radiation energy transfer theory, the binding distance between NCP-EDA and BSA was calculated to be 3.63 nm. In addition, the effect of NCP-EDA on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy. 相似文献
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Wu D Chen Z Liu X 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,84(1):178-183
The interaction between bovine serum albumin (BSA) and ZnS quantum dots (QDs) was studied by fluorescence, UV-vis spectroscopic techniques. The results showed that the fluorescence of BSA was strongly quenched by ZnS QDs and the quenching mechanism was discussed to be a static quenching procedure, which was proved by quenching rate constant K(q.) The recorded UV-vis data and the fluorescence data quenching by the QDs demonstrated that the interaction between them leads to the formation of QDs-BSA complex. Furthermore, the temperature effects on the structural and spectroscopic properties of individual QDs and protein and their bioconjugates (QDs-BSA) were also researched. It was found that, compared to the monotonically decrease of the individual QDs fluorescence intensity, the temperature dependence of the QDs-BSA emission had a much more complex behavior, highly sensitive to the conformational changes of the protein. 相似文献
8.
P.N. Naik S.A. Chimatadar S.T. Nandibewoor 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,73(5):841-845
The binding of sulfamethoxazole (SMZ) to bovine serum albumin (BSA) was investigated by spectroscopic methods viz., fluorescence, FT-IR and UV–vis absorption techniques. The binding parameters have been evaluated by fluorescence quenching method. The thermodynamic parameters, ΔH°, ΔS°and ΔG° were observed to be −58.0 kJ mol−1, −111 J K−1 mol−1 and −24 kJ mol−1, respectively. These indicated that the hydrogen bonding and weak van der Waals forces played a major role in the interaction. Based on the Forster's theory of non-radiation energy transfer, the binding average distance, r, between the donor (BSA) and acceptor (SMZ) was evaluated and found to be 4.12 nm. Spectral results showed the binding of SMZ to BSA induced conformational changes in BSA. The effect of common ions and some of the polymers used in drug delivery for control release was also tested on the binding of SMZ to BSA. The effect of common ions revealed that there is adverse effect on the binding of SMZ to BSA. 相似文献
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WANG Weiping TANG Jianghong PENG Xuhong HU Zhide & CHEN Xingguo Department of Chemistry Lanzhou University Lanzhou China 《中国科学B辑(英文版)》2006,49(4):332-337
1 Introduction Studies on the interaction of the complexes formed between proteins and amphiphilic molecules in aque- ous solutions have become a new focus and great pro- gress has been made in recent years[1―5]. An under- standing of these systems is of great importance in many biological processes and clinical use of drugs. The globular anionic protein human serum albumin (HSA) is widely used as a protein model in many studies[1―4,6]. Its principal function is to transport fatty acids an… 相似文献
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Hui Lin Jingfeng Lan Min Guan Fenling Sheng Haixia Zhang 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,73(5):936-941
The mechanism of interaction between mangiferin (MA) and bovine serum albumin (BSA) in aqueous solution was investigated by fluorescence spectra, synchronous fluorescence spectra, absorbance spectra and Fourier transform infrared (FT-IR) spectroscopy. The binding constants and binding sites of MA to BSA at different reaction times were calculated. And the distance between MA and BSA was estimated to be 5.20 nm based on Föster's theory. In addition, synchronous fluorescence and FT-IR measurements revealed that the secondary structures of the protein changed after the interaction of MA with BSA. As a conclusion, the interaction between the anti-diabetes Chinese medicine MA and BSA may provide some significant information for the mechanism of the traditional chinese medicine MA on the protein level to cure diabetes or other diseases. 相似文献
14.
Wang Z Li D Jin J 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,70(4):866-870
The interaction between lysozyme (LYSO) and puerarin has been studied at three temperatures (294, 302 and 310K) through/using fluorescence spectroscopy and circular dichroism (CD). The LYSO fluorescence was quenched by the binding of puerarin to LYSO. The binding constants and the number of binding sites can be calculated from the data obtained from fluorescence quenching experiments. According to the van't Hoff equation, the standard enthalpy change (DeltaH degrees ) and standard entropy change (DeltaS degrees ) for the reaction were calculated to be 17.47kJ/mol and 163.5J/molK. It indicated that the hydrophobic interactions play a main role in the binding of puerarin to LYSO. In addition, the distance between puerarin (acceptor) and tryptophan residues of LYSO (donor) was estimated to be 1.47nm on the basis of fluorescence energy transfer. The changes of LYSO secondary structure in the presence of puerarin were observed from CD spectroscopy. 相似文献
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Fei Ding Wei Liu Xi Zhang Li-Jun Wu Li Zhang Ying Sun 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(3):1088-1094
Pyrazosulfuron-ethyl (PY) is a sulfonylurea herbicide developed by DuPont which has been widely used for weed control in cereals. The determination of PY binding affinity and binding site in human serum albumin (HSA) by spectroscopic methods is the subject of this work. From the fluorescence emission, circular dichroism and three-dimensional fluorescence results, the interaction of PY with HSA caused secondary structure changes in the protein. Fluorescence data demonstrated that the quenching of HSA fluorescence by PY was the result of the formation of HSA–PY complex at 1:1 molar ratio, a static mechanism was confirmed to lead to the fluorescence quenching. Hydrophobic probe 8-anilino-1-naphthalenesulfonic acid (ANS) displacement results show that hydrophobic patches are the major sites for PY binding on HSA. The thermodynamic parameters ΔH° and ΔS° were calculated to be ?36.32 kJ mol?1 and ?35.91 J mol?1 K?1, which illustrated van der Waals forces and hydrogen bonds interactions were the dominant intermolecular force in stabilizing the complex. Also, site marker competitive experiments showed that the binding of PY to HSA took place primarily in subdomain IIA (Sudlow's site I). What presented in this paper binding research enriches our knowledge of the interaction between sulfonylurea herbicides and the physiologically important protein HSA. 相似文献
17.
用荧光光谱及紫外光谱法模拟研究生理条件下胡椒酸与牛血清白蛋白(BSA)的相互作用。结果表明,胡椒酸与BSA形成基态复合物从而猝灭BSA的内源性荧光,猝灭原因主要为静态猝灭和非辐射能量转移。胡椒酸对BSA的猝灭速率常数Kq为2.969×1013(18℃)、2.491×1013(25℃)和2.328×1013L·mol-1·s-1(37℃)。胡椒酸与BSA的结合常数KA为1.01×105(18℃)、2.06×104(25℃)和1.02×104L·mol-1(37℃),结合位点数n为0.90(18℃)、0.77(25℃)和0.72(37℃)。根据Frster偶极-偶极非辐射能量转移理论得到结合距离r为2.47(18℃)、2.52(25℃)和2.54(37℃)nm。确定胡椒酸与BSA有较强的相互作用,可以被蛋白质所储存和运输。 相似文献
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阿魏酸哌嗪与牛血清白蛋白相互作用的研究 总被引:5,自引:0,他引:5
在模拟人体生理条件下,用常规荧光光谱法和紫外-可见吸收光谱法研究阿魏酸哌嗪和牛血清白蛋白结合反应的特征,并利用同步荧光法和三维荧光法研究了阿魏酸哌嗪与牛血清白蛋白作用前后白蛋白的构象变化.研究表明:阿魏酸哌嗪与牛血清白蛋白形成复合物,从而猝灭牛血清白蛋白的内源性荧光.该过程为静态猝灭过程.根据Stem-Volmer方程求出不同温度下的结合位点数和结合常数;根据Fsmter非辐射能量转移理论可求出其作用距离r=2.33nm:根据基本热力学参数△H、△S和△G判断阿魏酸哌嗪和牛血清白蛋白主要通过氢键和范德华力发生相互作用. 相似文献