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荧光光谱法研究丙酮与牛血清白蛋白的相互作用特征 总被引:6,自引:0,他引:6
在模拟动物体生理条件和不同温度下,用荧光光谱、三维荧光光谱、同步荧光光谱、紫外可见吸收光谱法等研究了丙酮(ACET)与牛血清白蛋白(BSA)的相互作用,证实了丙酮有很强的猝灭BSA荧光强度的能力.分别用Sterr-Volmer方程、Lineweaver-Burk双倒数方程和热力学方程等分析和处理试验数据,得到了它们相互作用的生成常数KLV(平均值为7.073×106L·mol-1)、热力学参数(△Hθ、△Gθ和△Sθ的平均值分别为-3.982kJ·mol-1、-26.51 kJ·mol-1和73.31J·K-1)和结合位点数(平均值为1.266)等.这为研究ACET对BSA构象的影响、ACET的毒理效应和生物学效应提供了重要信息. 相似文献
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Combined fluorescence and electrochemical investigation on the binding
interaction between organic acid and human serum albumin 总被引:1,自引:1,他引:0
Human serum albumin (HSA) is a plasma protein responsible for the binding and transport of fatty acids and a variety of exogenous chemicals such as drugs and environmental pollutants. Such binding plays a crucial role in determining the ADME (absorption, distribution, metabolism, and excretion) and bioavailability of the pollutants. We report investigation on the binding interaction between HSA and acetic acid (C2), octanoic acid (C8) and dodecanoic acid (C12) by the combination of site-specific fluorescent probe, tryptophan intrinsic fluorescence and tyrosine electrochemistry. Two fluorescent probes, dansylamide and dansyl-L-proline, were employed in the displacement measurement to study fatty acid interaction with the two drug-binding sites on HSA. Intrinsic fluorescence of tryptophan in HSA was monitored upon addition of the fatty acids into HSA. Electrocatalyzed response of the tyrosine residues in HSA by a redox mediator was used to investigate the binding interaction. Qualitatively, observations made by the three approaches are very similar. HSA did not show any change in either fluorescence or electrochemistry after mixing with C2, suggesting there is no significant interaction with the short-chain fatty acid. For C8, the measured signal dropped in a single-exponential fashion, indicative of independent and non-cooperative binding. The calculated association constant and binding ratio is 3.1×106 L/mol and 1 with drug binding Site I, 1.1×107 L/mol and 1 with Site II, and 7.0×104 L/mol and 4 with the tryptophan site. The measurement with C12 displayed multiple phases of fluorescence change, suggesting cooperativity and allosteric effect of C12 binding. These results correlate well with those obtained by the established methods, and validate the new approach as a viable tool to study the interactions of environmental pollutants with biological molecules. 相似文献
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掌叶大黄是中国传统的药用植物,其主要活性成分为蒽醌类化合物.利用人血清白蛋白(Human serumalbumin,HSA)功能化的磁性纳米粒子(Magnetic nanoparticles,MNPs)为固相萃取材料,对掌叶大黄的水提取液进行配体垂钓研究,从中捕获到两个HSA的配体;结合质谱鉴定其结构分别为大黄素和大黄酚.基于磁性纳米粒子的配体垂钓技术可为从传统药用植物中寻找HSA的小分子配体提供一个简便有效的方法. 相似文献
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硝基苯胺同牛血清白蛋白的相互作用及其毒性 总被引:4,自引:0,他引:4
运用毛细管电泳相互作用分析的峰漂移模型 ,在接近于生物大分子与配体作用所需要的生理条件下 ,测定了典型有机物邻 、间 、对 硝基苯胺三种化合物共存时与牛血清白蛋白的相互作用的结合常数 .结合常数大小顺序是 :邻 硝基苯胺 >对 硝基苯胺 >间 硝基苯胺 .根据三种物质作用前后紫外吸收强度的变化推算出的结果与实验结果具有一致性 .对这些结合常数与该三种物质的生物实验毒性她据及其分子结构参数的相关性进行比较分析 ,发现它们之间存在一定的相关性 .这表明用毛细管电泳相互作用分析方法评价硝基苯胺的生物毒性具有一定可行性 . 相似文献
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钙离子存在下胞外聚合物及其模拟溶液在膜污染中的差异 总被引:1,自引:0,他引:1
针对膜生物反应器膜污染的问题,为探究模拟物质替代实际物质的可行性,以胞外聚合物(EPS)及其模拟溶液(BSA+SA)为研究对象,对比了钙离子(Ca~(2+))存在下胞外聚合物及其模拟溶液在膜污染中的差异,考察了EPS-Ca~(2+)和BSA+SA-Ca~(2+)在粒径分布、官能团、流变特性和膜污染行为等方面的差异。结果表明:Ca~(2+)使得溶液粒径变大,且EPS-Ca~(2+)的平均粒径大于BSA+SA-Ca~(2+)的平均粒径;不同官能团与Ca~(2+)发生作用导致红外光谱中特征峰发生偏移;BSA+SA-Ca~(2+)水胶体系结构更稳定,随着应变的增大,胶体结构被破坏的程度较轻;在微滤过程中,相同操作条件下,BSA+SA-Ca~(2+)的膜污染现象更为严重。进一步采用Hermia过滤模型拟合发现,EPSCa~(2+)和BSA+SA-Ca~(2+)分别对中间堵塞模型和滤饼层过滤模型的拟合程度最高。上述结果可为膜污染过程中胞外聚合物及其膜污染机理研究提供参考。 相似文献
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在模拟生理条件下(pH7.4),采用荧光光谱研究环境污染物全氟辛酸(PFOA)与牛血清白蛋白(BSA)的相互作用.结果表明,PFOA对BSA有荧光静态猝灭作用.PFOA与BSA在温度277,298,310K的反应结合常数分别为1.06×105,7.12×104,5.68×104L/mol;在BSA上有1个PFOA的结合位点,该位点更接近于色氨酸残基.由反应的热力学可推断PFOA与BSA的相互作用力主要是静电引力和疏水作用力.与PFOA结合后,BSA分子构象发生变化,色氨酸残基附近疏水性增强,蛋白质分子结构趋于折叠状态;而酪氨酸残基附近亲水性增强,蛋白质分子结构趋于松散状态. 相似文献
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ZHAO Changwei ZHANG Jingbo LUAN Zhaokun PENG Xianjia REN Xiaojing 《环境科学学报(英文版)》2009,21(10):1342-1346
A novel membrane distillation concentration method was used to prepare high concentration polyaluminum chloride (PACl) with high content of Alb or Alc. 2.52 mol/L PACl1 with 88% Alb and 2.38 mol/L PACl2 with 61% Alc were successfully prepared. Three coagulants, AlCl3, PACl1 and PACl2 were investigated on their hydrolysis behavior and speciation under different conditions. The effects of pH and dilution ratio on Al species distribution were investigated by ferron assay. Experimental result showed that pH had a significant effect on Al species distribution for the three coagulants. Dilution ratio had little effects on Alb and Alc distribution in whole dilution process except the beginning for PACl1 and PACl2. The results indicated that transformation of Al depends largely on their original composition. AlCl3 was the most unstable coagulant among these three coagulants during hydrolysis process. PACl1 and PACl2 with significant amounts of highly charged and stable polynuclear aluminum hydrolysis products were less affected by the hydrolysis conditions and could maintain high speciation stability under various conditions. 相似文献
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Bisphenol A (BPA) is a chemical with high production volume and wide applications in many industries. Although BPA is known
as an endocrine disruptor, its toxic mechanisms have not been fully characterized. Due to its structural similarity to thyroid hormones
thyroxine (T4) and triiodothyronine (T3), one possible mechanism of BPA toxicity is disruption of hormone transport by competitive
binding with the transport proteins. In this study, the binding interactions of BPA, T4, and T3 with three thyroid hormone transport
proteins, human serum albumin (HSA), transthyretin (TTR), and thyroxine-binding globulin (TBG) were investigated by fluorescence
measurement. Using two site-specific fluorescence probes dansylamide and dansyl-L-proline, the binding constants of BPA with HSA
at drug site I and site II were determined as 2.90 104 and 3.14 104 L/mol, respectively. By monitoring the intrinsic fluorescence
of tryptophan, a binding constant of 4.70 103 L/mol was obtained. Similarly, by employing 8-anilino-1-naphthalenesulfonic acid as
fluorescence probe, the binding a nity of BPA with TTR and TBG was measured to be 3.10 105 and 5.90 105 L/mol, respectively.
In general, BPA showed lower binding a nity with the proteins than T3 did, and even lower a nity than T4. Using these binding
constants, the amount of BPA which would bind to the transport proteins in human plasma was estimated. These results suggest that
the concentrations of BPA commonly found in human plasma are probably not high enough to interfere with T4 transport. 相似文献