诺氟沙星与牛血清白蛋白相互作用的研究

用荧光光谱法研究诺氟沙星与牛血清白蛋白之间的结合作用,确定了诺氟沙星与牛血清白蛋白的荧光猝灭机制为静态猝灭。通过测定和计算不同温度下该结合反应的结合常数和结合位点数,并根据热力学方程求得了结合反应的热力学参数,讨论了两者问的主要作用力类型是范德华力和氢键。同时采用同步荧光技术考察了诺氟沙星对BSA构象的影响。并从荧光寿命进一步证明诺氟沙星与牛血清白蛋白的荧光猝灭机制为静态猝灭。     

聚乙二醇修饰牛血清白蛋白的反应与分析

采用N,N′-羰基二咪唑活化法活化单甲氧基聚乙二醇5000分子一端的羟基,对活化后的单甲氧基聚乙二醇分子进行了元素分析。用该活化产物对牛血清白蛋白的赖氨酸侧链氨基进行化学修饰。应用毛细管电泳对聚乙二醇修饰后的产物进行了分析,并与高效液相色谱分析结果作了对照研究,表明毛细管电泳对修饰后的牛血清白蛋白有更好的分析效果。     

表面活性剂增敏——牛血清白蛋白荧光猝灭法测定槐花中芦丁含量

目的：应用牛血清白蛋白荧光猝灭法建立一种测定槐花中芦丁含量的新方法。方法：牛血清白蛋白（BSA）具有很强的内源荧光性,而芦丁溶液本身不产生荧光。当芦丁与BSA结合后,会导致其荧光强度下降,表面活性剂吐温-80（T-80）对体系有促进荧光猝灭作用。BSA在λex=338nm处的荧光猝灭程度与芦丁的量在一定浓度范围内呈良好的线性关系,据此建立测定槐花中芦丁含量的新方法。结果：该结合物的最大发射波长为λmax=338nm,与芦丁摩尔浓度在6×10-7-3.0×10-5mol.L-1范围内线性关系良好。其线性回归方程为ΔF=136.36CRu（×10-5mol.L-1）-0.5454,相关系数r=0.9976,检出限为1.58×10-7mol.L-1,RSD为2.8%-4.3%,加标回收率为97.6%~101.2%。结论：本方法操作简便、快速,用于实际样本的测定,结果满意。     

超声和高压处理对牛血清白蛋白结构的影响

目的:研究牛血清白蛋白经过超声和高压处理前后的结构变化,以及自由基清除剂对其结构变化的影响.为进一步研究细胞破碎和乳化蛋白时超声和高压处理对蛋白的影响提供参考.方法:将BSA溶液经过超声和高压处理,然后利用高效液相色谱(HPLC)、动态光散射(DLS)、非变性聚丙烯酰胺凝胶电泳(nondenaturing SDS-PAGE)以及园二色谱(CD)等手段检测处理前后的结构变化.结果:发现超声使BSA严重聚集,加入自由基清除剂可以减少聚集的产生.而高压处理后的BSA未出现聚集,但二级结构发生了变化.结论:超声和高压这两种处理方法对蛋白损伤机理不同,所以选择合适的破碎方法要根据蛋白自身的性质而定.     

超声和高压对牛血清白蛋白结构的影响比较

目的：研究牛血清白蛋白经过超声和高压处理前后的结构变化,以及自由基清除剂对其结构变化的影响。为进一步研究细胞破碎和乳化蛋白时超声和高压处理对蛋白的影响提供参考。方法：将BSA溶液经过超声和高压处理,然后利用高效液相色谱（HPLC）、动态光散射（DLS）、非变性聚丙烯酰胺凝胶电泳（nondenaturing SDS PAGE）以及园二色谱（CD）等手段检测处理前后的结构变化。结果：发现超声使BSA严重聚集,加入自由基清除剂可以减少聚集的产生。而高压处理后的BSA未出现聚集,但二级结构发生了变化。结论：超声和高压这两种处理方法对蛋白损伤机理不同,所以选择合适的破碎方法要根据蛋白自身的性质而定。     

粘度法研究牛血清白蛋白的溶液行为

经粘度法测量证明牛血清白蛋白在NaCl,KSCN和KI3种盐溶液中的流体力学行为有较大差别,并按经验公式由粘度数据计算了表观分子轴比和分子体积,它们也随盐的种类不同而相应变化．     

金属离子对盐酸多西环素与牛血清白蛋白的结合常数的影响

利用荧光光谱法、紫外光谱法研究了盐酸多西环素与牛血清白蛋白的作用。还研究了不同浓度的Ca2+、Mg2+、Zn2+、Cu2+、Fe3+存在时,对盐酸多西环素与血清白蛋白的相互作用的影响。金属离子的存在能够影响盐酸多西环素与BSA结合,使其反应的表观结合常数值降低了,并且反应常数随Ca2+、Mg2+、Zn2+浓度的增加而降低。     

水溶性壳聚糖与牛血清白蛋白相互作用的研究

采用紫外和荧光光谱研究了水溶性壳聚糖(CS)与牛血清白蛋白(BSA)之间的相互作用。结果表明:随CS浓度的增加,BSA的紫外吸收光谱表现出明显的增色效应和较小的紫移;CS可以猝灭BSA的内源荧光,其猝灭机理是CS与BSA形成复合物的静态猝灭。并且测定了在不同温度下,该反应的结合常数KA分别为6.92×106(298 K),5.01×106(308 K),3.31×106(318 K),CS与BSA以摩尔比1∶1结合。同时采用同步荧光光谱法探讨了CS对BSA构象的影响。     

The Interaction of New Pyridylporphyrins with Bovine Serum Albumin

The interaction of meso-tetra(4-N-hydroxyethylpyridyl)porphyrin, meso-tetra(3-N-hydroxyethylpyridyl)porphyrin, and their zinc complexes with bovine serum albumin (BSA) was studied by electronic spectroscopy, CD, and equilibrium dialysis at pH 7.2. The titration of the porphyrins with BSA was accompanied by a decrease in light absorption and a bathochromic shift of the Soret band, as well as by the appearance of an isobestic point. The porphyrin interaction with BSA also led to the induction of positive CD spectra in the visible region, which is explained by the porphyrin sorption on the protein globule. The equilibrium dialysis helped in determining the stoichiometry of binding and the binding constants of the porphyrins under study with BSA using Scatchard plots. This interaction is nonspecific and reversible.     

人和牛血清白蛋白的极谱测定

人或牛血清白蛋白溶液调至ｐＨ１０并在４℃左右放置３０ｈ,诱导出重复性良好的极谱峰。然后把试样溶液调至适当ｐＨ并记录极谱电流。在浓度低于１．０×１０－５ｍｏｌ／Ｌ时,峰电流对浓度作图是直线,试样浓度可从图上直接读出。对影响白蛋白测定的诸因素作了详细研究和讨论。结果对富含硫的蛋白质的极谱研究有参考价值。     

壳聚糖钴与牛血清白蛋白相互作用的研究

采用紫外-可见吸收和荧光光谱,研究了壳聚糖钴与牛血清白蛋白(BSA)的相互作用。结果发现:随壳聚糖钴浓度的增加,BSA的紫外-可见吸收光谱表现增色效应和较小的蓝移;壳聚糖钴可以猝灭BSA的内源荧光,其猝灭机理属于静态猝灭。在室温下,壳聚糖钴与BSA的的结合常数KA为2.40×106。     

Kinetics of Thermal Denaturation and Aggregation of Bovine Serum Albumin

Thermal aggregation of bovine serum albumin (BSA) has been studied using dynamic light scattering, asymmetric flow field-flow fractionation and analytical ultracentrifugation. The studies were carried out at fixed temperatures (60°C, 65°C, 70°C and 80°C) in 0.1 M phosphate buffer, pH 7.0, at BSA concentration of 1 mg/ml. Thermal denaturation of the protein was studied by differential scanning calorimetry. Analysis of the experimental data shows that at 65°C the stage of protein unfolding and individual stages of protein aggregation are markedly separated in time. This circumstance allowed us to propose the following mechanism of thermal aggregation of BSA. Protein unfolding results in the formation of two forms of the non-native protein with different propensity to aggregation. One of the forms (highly reactive unfolded form, U_hr) is characterized by a high rate of aggregation. Aggregation of U_hr leads to the formation of primary aggregates with the hydrodynamic radius (R_h,1) of 10.3 nm. The second form (low reactive unfolded form, U_lr) participates in the aggregation process by its attachment to the primary aggregates produced by the U_hr form and possesses ability for self-aggregation with formation of stable small-sized aggregates (A_st). At complete exhaustion of U_lr, secondary aggregates with the hydrodynamic radius (R_h,2) of 12.8 nm are formed. At 60°C the rates of unfolding and aggregation are commensurate, at 70°C the rates of formation of the primary and secondary aggregates are commensurate, at 80°C the registration of the initial stages of aggregation is complicated by formation of large-sized aggregates.     

多西紫杉醇白蛋白微球的制备及优化实验研究

多西紫杉醇(DT)是唯一应用于临床治疗肿瘤的紫杉醇的衍生物,其水溶性差,制剂中需要加入有机溶剂和助溶剂,而有机溶剂和助溶剂具有刺激性。为减少多西紫杉醇制剂的刺激性,本实验通过去溶剂化—化学交联法制备水溶性多西紫杉醇白蛋白微球。对制备过程中的重要影响因素进行考察,并通过Design-expert软件进行数据优化,最终得优化条件:白蛋白浓度为35 mg.mL-1,DT浓度为1.03 mg.mL-1,乙醇和水的比例为3∶1,乙醇的滴加速度为0.73 mL.min-1,搅拌时间为12 h,0.2%戊二醛与白蛋白的交联比为2∶1。得到的多西紫杉醇白蛋白微球粒径为185 nm,载药量为14.4%,成功的解决了其水溶性,为接下来的动物实验、临床应用提供了良好的基础。     

Stabilization of Colicin E2 by Bovine Serum Albumin

Colicin E2 was partially purified from Escherichia coli W3110. This preparation was remarkably stabilized by bovine serum albumin in a solution at neutral pH, as shown by dilution experiments and tests on heat stability of colicin. One killing unit of colicin E2 was estimated to correspond to one molecule of colicin E2, on the assumption of a molecular weight of 60,000.     

The Effect Of Commercial Bovine Serum Albumin And Other Proteins On The Activity Of Bovine Milk Galactosyltransferase

Abstract

The widespread use of bovine serum albumin preparations for the stabilization of purified glycosyltransferases has prompted us to study the effects of different preparations of albumins on the galactosyltransferase activity of bovine milk. For comparison, several other proteins were tested as well. The albumins caused a large stimulation of transferase activity (400–700%) which varied depending on the source of the albumin and the treatment to which it had been subjected. Several other unrelated proteins were tested for their effects on transferase activity. Some proteins stimulated, while others had little effect. Lysozyme stimulated the activity by 178% and poly-L-lysine had Vittle effect. Other proteins stimulated to variable extents. The stimulations obtained with albumin and myelin basic protein were noteworthy. The stimulation was considerably less marked when the enzyme was incorporated into lipid vesicles.     

Bovine Serum Albumin Binding and Drug Delivery Studies with PVA-Ferrofluid

This paper describes a single-step method for the biomimetic synthesis of stably suspended magnetite nanoparticles in poly(vinyl alcohol) termed ferrofluids. The challenge is to synthesize water based stable magnetic colloids with a control over the particle size and morphology for biomedical applications. The polymer possibly plays a dual role of a surfactant and a functionalizing agent. Transmission electron microscopy, infrared spectroscopy and vibrating sample magnetometry were used to investigate the properties of the synthesized ferrofluids. It has a strong affinity towards the tryptophan residues in bovine serum albumin protein as determined from the fluorescence emission studies. For in vivo applications this could indirectly mean a resistance to immune response and thus ensure long-term circulation. The ability of the synthesized ferrofluid to bind a che-motherapeutic drug ceftriaxone and its ionic release was observed. The polymer hydroxyl group allows drug-binding and the magnetic property allows targeting to specific sites. Magnetic hybrid fluids with combined advantages of magnetism and polymer open up new perspectives for applications.