Budama Battal Yasemin, Topuzogullari Murat, Mustafaeva Zeynep
Department of Bioengineering, Faculty of Chemical and Metallurgical Engineering, Yildiz Technical University, 34220, Esenler, Istanbul, Turkey,
J Fluoresc. 2009 Apr 28. doi: 10.1007/s10895-009-0484-9.
The complex formation of Bovine Serum Albumin (BSA) with anionic polyelectrolyte (polyacrylic acid, PAA) in aqueous solution was studied by a fluorescence technique, pH titration and HPLC analysis. The character of the interactions and solubility of the polycomplex particles depends on the BSA/PAA ratios and the pH of solution. The interaction at pH > pI (isoelectric point of BSA) (pH 6.0-7.0) is negligible weak and at pH 5.0 results with the formation of stable water-soluble polycomplexes at a wide range of protein/polymer ratios. The fluorescence intensity of BSA sharply decreased when an different amount of PAA was added and its maximum wavelength shifts towards the blue region. The protein molecules in the structure of soluble polycomplex particles are densely covered by the shelf of a polymer coil and practically "fenced off" from the water environment. This effect was reinforced by the increase of protein components. Existence of soluble and insoluble PAA-BSA complexes have been observed at pH < pI (pH 4.0-4.3). These soluble complexes characterized by the structure of particles in which protein molecules are densely covered by the shelf of a polymer coil. By the increase in the protein concentration, these complexes aggregate to an interpolymer species.
采用荧光技术、pH滴定和高效液相色谱分析研究了牛血清白蛋白（BSA）与阴离子聚电解质（聚丙烯酸，PAA）在水溶液中的复合形成。聚络合物颗粒的相互作用特性和溶解性取决于BSA/PAA的比例以及溶液的pH值。在pH > pI（BSA的等电点）（pH 6.0 - 7.0）时相互作用非常微弱，而在pH 5.0时，在很宽的蛋白质/聚合物比例范围内会形成稳定的水溶性聚络合物。当加入不同量的PAA时，BSA的荧光强度急剧下降，其最大波长向蓝色区域移动。可溶性聚络合物颗粒结构中的蛋白质分子被聚合物线圈的支架密集覆盖，实际上与水环境“隔离”。蛋白质成分的增加增强了这种效果。在pH < pI（pH 4.0 - 4.3）时观察到了可溶性和不溶性的PAA - BSA络合物。这些可溶性络合物的颗粒结构特征是蛋白质分子被聚合物线圈的支架密集覆盖。随着蛋白质浓度的增加，这些络合物聚集成聚合物间的物种。
