荧光光谱法研究塞曲司特与牛血清白蛋白的相互作用

目的:研究不同pH条件下塞曲司特与牛血清白蛋白的相互作用机制.方法:利用荧光光谱法,并以Stern-Volmer方程确定药物与蛋白的作用类型.结果:根据Stern-Volmer方程求出了不同二者pH条件下塞曲司特与牛血清白蛋白之间的猝灭常数,并依据 Foster能量转移理论确定了生理条件下药物与蛋白的结合距离为 2.53 nm.结论:在pH 5.0和人体生理pH条件下塞曲司特对牛血清白蛋白具有荧光猝灭作用且为动态猝灭过程,在pH 8.4时塞曲司特与牛血清白蛋白之间的猝灭为静态猝灭;人体生理pH条件下塞曲司特与牛血清白蛋白之间相互作用力主要为范德华力.     

卡马西平与牛血清白蛋白的相互作用

目的研究卡马西平(CBZ)与牛血清白蛋白(BSA)在缓冲溶液中、不同温度下的相互作用。方法采用荧光光谱法和紫外光谱法。结果运用荧光猝灭双倒数图计算在不同条件下二者的结合常数KA;根据F rster非辐射能量转移理论,求出37℃时给体(BSA)和受体(CBZ)之间能量转移的效率和结合距离;并根据热力学参数确定了CBZ和BSA之间的作用力类型。结论CBZ和BSA之间有较强的相互作用,以疏水作用力为主。同步荧光技术表明,CBZ对BSA的构象有影响。     

灯盏乙素与牛血清白蛋白相互作用的研究

目的采用荧光、紫外光谱法研究在模拟人体生理条件下灯盏乙素与牛血清白蛋白(BSA)之间的相互作用。方法将灯盏乙素对牛血清白蛋白进行荧光淬灭滴定,利用Scatchard模型和F"rster非辐射能量转移理论得出灯盏乙素和牛血清白蛋白的结合参数。结果灯盏乙素与BSA的结合常数K=1.240×106,结合距离r=2.94nm,相互作用力主要为疏水作用力。结论阐明了灯盏乙素和牛血清白蛋白相互作用的机制,建立了灯盏乙素和牛血清白蛋白的结合模型。     

荧光光谱法研究芒柄花素与牛血清白蛋白的相互作用

在模拟动物体生理条件下,用荧光光谱法研究芒柄花素(hq-2)与牛血清白蛋白(BSA)的结合作用.结果 表明,芒柄花素对BSA荧光猝灭属于静态猝灭;并求得结合常数Ka为5.27×104L·mol-1,结合位点数为1.热力学数据表明该药物与牛血清白蛋白的相互作用是一个吉布斯自由能降低的自发过程,且二者之间的主要作用力类型为...     

木犀草素、芹菜素与牛血清白蛋白相互作用的研究

目的研究木犀草素、芹菜素与牛血清白蛋白(BSA)的相互作用机制。方法主要应用荧光猝灭法及非辐射能量转移原理。结果测得不同温度下，木犀草素、芹菜素与牛血清白蛋白的结合常数，确定两种黄酮小分子对牛血清白蛋白荧光的猝灭是静态猝灭过程，并依据能量转移原理求得其结合距离和能量转移效率。结论木犀草素、芹菜素与牛血清白蛋白间有较强的结合作用，且结合力以疏水作用力为主；B(3′)-OH，B(4′)-OH邻位对黄酮与牛血清白蛋白的结合具有增强作用。     

结晶紫与牛血清蛋白相互作用研究

运用荧光光谱和紫外-可见吸收光谱研究了在缓冲溶液中不同温度下结晶紫(CV)与牛血清白蛋白(BSA)之间的相互作用。实验结果表明,CV对BSA的内源荧光猝灭为静态猝灭过程。测定了该反应在不同温度下的结合常数KA,KA分别为1.49×105L.mol-1(25℃)、1.15×105L.mol-1(35℃)和1.01×105L.mol-1(45℃),CV与BSA以摩尔比1∶1结合。根据Forster非辐射能量转移理论,求出了37℃时给体(CV)和受体(BSA)之间结合距离为r=6.48nm。计算出的热力学参数表明,CV和BSA之间的作用力主要是通过疏水作用力相互作用。     

金合欢素-7-O-葡萄糖苷与BSA相互作用的荧光光谱法研究

应用荧光光谱法研究了生理条件下金合欢素-7-O-葡萄糖苷与牛血清白蛋白（BSA）的相互作用。结果表明,其对BSA荧光的猝灭机制属于形成复合物的静态猝灭过程,并求得结合常数Ka为8.57×104L.mol-1,结合位点数n为1。根据热力学参数确定了其与BSA之间的主要作用力类型为静电作用力。采用同步荧光考察了药物对BSA构象的影响。此外,讨论了共存离子Cu2＋,Al3＋,Zn2＋,Mg2＋对药物与BSA结合作用的影响。     

木犀草素与牛血清白蛋白相互作用的荧光光谱法研究

本文首次采用荧光光谱法研究传统中药白毛夏枯草中活性成分木犀草素与牛血清白蛋白（BSA）的猝灭机制。实验研究了木犀草素在291 k和310 k条件下与BSA的猝灭情况,通过计算求得不同温度下的热力学参数。结果表明木犀草素对牛血清白蛋白荧光的猝灭机制属于静态猝灭过程,二者之间的作用力主要为范德华力和氢键。此外,实验还考察了木犀草素对BSA构象的影响。     

巴氯芬及β-环糊精的包结物与牛血清白蛋白的相互作用研究

目的:研究巴氯芬及β-环糊精的包结作用和巴氯芬及β-环糊精包结物与牛血清白蛋白的相互作用。方法:用紫外可见分光光度法与核磁共振法研究了β-环糊精对巴氯芬的包结行为;用摩尔比法确定了包结物的化学计量比;用公式计算了不同温度下巴氯芬与β-环糊精的包结常数;用荧光光谱法研究了巴氯芬与包结物对牛血清白蛋白牛血清白蛋白的相互作用。结果:巴氯芬与β-环糊精的包结过程是自发的,主要驱动力为疏水作用力;巴氯芬及包结物都会对牛血清白蛋白产生静态猝灭。结论:巴氯芬与β-环糊精的包结比为1∶1;巴氯芬与牛血清白蛋白的主要作用为疏水作用,而包结物与牛血清白蛋白主要为静电作用,这是由于β-环糊精将巴氯芬分子中疏水部分包结的结果。     

环丙沙星与牛血清白蛋白的相互作用

血清白蛋白是血浆中含量最丰富的重要载体蛋白 ,药物进入血浆后 ,首先与血清白蛋白结合 ,然后再被运送到身体的各部位。随着药代动力学及临床药理学迅猛发展 ,药物 蛋白质结合对药代动力学影响 ,又有了更深刻的认识。因此 ,研究药物与血清白蛋白的相互作用有重要意义[1] 。本文应用荧光光度法研究了生理ｐＨ值条件下 ,环丙沙星与牛血清白蛋白 (ＢＳＡ)的相互作用 ,利用环丙沙星对蛋白质荧光的猝灭求出环丙沙星与蛋白质的结合常数 ,考察了药物对蛋白质构象的影响 ,并根据热力学参数确定了它们之间的主要作用力类型。这对阐明药物在体内的输…     

曲克芦丁与牛血清白蛋白的相互作用研究

目的采用荧光光谱法和紫外吸收光谱法研究曲克芦丁与牛血清白蛋白(BSA)结合反应的特征。方法将曲克芦丁对BSA内源性荧光的猝灭数据分别应用Stern-Volmer方程和Lineweaver-Burk双倒数方程计算反应的荧光猝灭常数和结合常数,应用双对数方程计算结合位点数,热力学公式计算二者结合主要作用力类型,在此基础上应用Frster非辐射能量转移理论,计算曲克芦丁与BSA相互结合时给体-受体间的距离和能量转移效率。结果结果表明曲克芦丁能够有效降低BSA的内源性荧光,其猝灭机制属于静态猝灭,二者之间的结合力为疏水作用力,二者的结合常数为106数量级,结合位点数为1,作用距离为1.97nm,能量转移效率为0.529。结论曲克芦丁可与BSA通过疏水作用结合为复合物,经静态猝灭机制引起BSA内源性荧光的猝灭。     

黄芩素及黄芩苷与牛血清白蛋白结合作用比较研究及葡萄糖的影响

目的比较研究黄芩素和黄芩苷与牛血清白蛋白(BSA)分子间的结合作用及机制。方法通过光谱法比较研究黄芩素和黄芩苷与BSA结合作用,并观察葡萄糖对二者与BSA结合的影响。以能量传递原理和Lineweaver-Burk双倒数方程计算二者与BSA反应的结合常数和结合距离;以热力学参数判断二者与BSA间的作用力类型;以同步荧光技术考察黄芩素和黄芩苷对BSA构象的影响。结果黄芩素和黄芩苷与BSA反应的结合常数和结合距离均随着温度的升高而降低;与黄芩素相比,黄芩苷与BSA的结合距离增大,作用强度减弱。葡萄糖能明显增加二者与BSA的结合常数及结合位点。黄芩素与BSA的结合力为氢键和范德华力、黄芩苷为静电引力,从而导致BSA内在荧光静态猝灭。黄芩素和黄芩苷均能使BSA构象发生变化,黄芩素还能使BSA的色氨酸所处环境的疏水性降低。结论黄芩素分子上糖取代可降低其与BSA之间的结合作用并改变其作用力类型。生理浓度的葡萄糖可明显增加黄芩素和黄芩苷与BSA的结合常数及结合位点。     

氧氟沙星与牛血清白蛋白相互作用机制

目的　以光谱技术与微量热技术相结合的方法研究水溶液中牛血清白蛋白与氧氟沙星分子间结合作用的机制。方法　用荧光猝灭法及微量热法。结果　荧光猝灭法测得该反应的结合常数K=1.20×105 L.mol^-1,结合位点数n=1.20,微量热法测得反应的焓变Δ_rH_m≈0;用同步荧光技术考察氧氟沙星对牛血清白蛋白构象的影响;依据Fōrster非辐射能量转移机制,得到授体-受体间的结合距离(r=2.59 nm)和能量转移效率(E=0.38)。结论　牛血清白蛋白与氧氟沙星分子间有较强的结合作用,且结合力以疏水作用为主。     

Spectroscopic studies on the interaction between silicotungstic acid and bovine serum albumin

The interaction between silicotungstic acid and bovine serum albumin (BSA) was investigated using fluorescence and UV/vis. The experimental results showed that the fluorescence quenching of BSA by silicotungstic acid is a result of the formation of SiW–BSA complex; static quenching and non-radiative energy transferring were confirmed to result in the fluorescence quenching. The binding site number n, apparent binding constant K_A and corresponding thermodynamic parameters were measured at different temperatures. The process of binding SiW molecule on BSA was a spontaneous molecular interaction procedure in which entropy increased and Gibbs free energy decreased. Hydrophobic interaction force plays a major role in stabilizing the complex. The effect of silicotungstic acid on the conformation of BSA was analyzed using synchronous fluorescence spectroscopy.     

Study of the interaction of an anticancer drug with human and bovine serum albumin: spectroscopic approach

The interactions between gemcitabine hydrochloride (GEM) and bovine serum albumin (BSA) or human serum albumin (HSA) have been studied by spectroscopic techniques. By the analysis of fluorescence spectrum and fluorescence intensity, it was observed that the GEM has a strong ability to quench the intrinsic fluorescence of both BSA and HSA through a static quenching procedure. The association constants of GEM with BSA and HSA were determined at different temperatures based on fluorescence quenching results. The negative ΔH° and positive ΔS° values in case of GEM–BSA and GEM–HSA complexes showed that both hydrogen bonds and hydrophobic interactions play a role in the binding of GEM to BSA or HSA. Experimental results showed that the binding of GEM to BSA or HSA induced conformational changes in BSA and HSA. From the quantitative analysis data of CD spectra, the α-helix of 57.58% and 34.82% in free BSA and free HSA decreased to 40.82% and 29.84% in BSA–GEM and HSA–GEM complexes, respectively, and hence confirmed that the secondary structure of protein was altered by GEM. The interactions of BSA and HSA with GEM were also confirmed by UV absorption spectra. The distance, r, between donor (BSA or HSA) and acceptor (GEM) was obtained according to the Förster's theory of non-radiation energy transfer. The effects of common ions on the binding constants of both BSA–GEM and HSA–GEM complexes were also investigated.     

Absorption and fluorescence study of the interaction between (2-hydroxy-benzimido)ethyl-n-hexylselenide and bovine serum albumin

The binding of Schiff base selenide, (2-hydroxy-benzimido)ethyl-n-hexylselenide, to bovine serum albumin (BSA) was studied using fluorescence spectroscopy. The measurement was performed in Tris-HCl buffer aqueous medium at pH 7.4. Stern-Volmer graphs were plotted and quenching constants were estimated. The quenching constant at 303 K was (1.639 +/- 0.046) x 10(13) L mol(-1) s(-1). Decreased quenching was observed as temperature increased, but at the temperature range of 303-313 K, the association of Schiff base selenide to BSA was not significantly different. The static quenching presented in the system of Schiff base selenide and BSA. A complex was possibly formed between Schiff base selenide and BSA, which was responsible for the quenching of the fluorescence of BSA. This fact was also confirmed by differences in the absorption spectra of BSA before and after Schiff base selenide addition. The hydrophobic interaction was found to play a main role in the binding according to the thermodynamic parameters, enthalpy change (DeltaH) and entropy change (DeltaS) of reaction. Schiff base selenide most likely binds to the hydrophobic pockets within sub domain IIA of BSA, which can be proved by competition experiments for sodium dodecyl sulfate. By constant-wavelength synchronous fluorescence spectra, the influence of (2-hydroxy-benzimido)ethyl-n-hexylselenide on the surrounding environment of tyrosine and tryptophan residues in BSA was also investigated. The red shift of the fluorescence peak of tryptophan residues indicated that the hydrophobic amino acid structure surrounding tryptophan residues in BSA collapsed slightly after the addition of (2-hydroxy-benzimido)ethyl-n-hexylselenide.