Grupo de Materiais Nanoestruturados, Campus Universitário do Araguaia, Universidade Federal de Mato Grosso, 78600-000 Barra do Garças, MT, Brazil.
Biomed Res Int. 2013;2013:461365. doi: 10.1155/2013/461365. Epub 2013 Jul 25.
This paper reports on the study of the interactions between ascorbic acid (AA) and bovine serum albumin (BSA) in aqueous solution as well as in films (BSA/AA films) prepared by the layer-by-layer technique. Regarding to solution studies, a hyperchromism (in the range of ultraviolet) was found as a function of AA concentration, which suggested the formation of aggregates from AA and BSA. Binding constant, K, determined for aggregates from BSA and AA was found to be about 10(2) M(-1), which indicated low affinity of AA with BSA. For the BSA/AA films, it was also noted that the AA adsorption process and surface morphological structures depended on AA concentration. By changing the contact time between the AA and BSA, a hypochromism was revealed, which was associated to decrease of accessibility of solvent to tryptophan due to formation of aggregates. Furthermore, different morphological structures of aggregates were observed, which were attributed to the diffusion-limited aggregation. Since most of studies of interactions of drugs and proteins are performed in solution, the analysis of these processes by using films can be very valuable because this kind of system is able to employ several techniques of investigation in solid state.
本文报告了抗坏血酸（AA）与牛血清白蛋白（BSA）在水溶液以及通过层层技术制备的薄膜（BSA/AA 薄膜）中的相互作用研究。关于溶液研究，发现了随着 AA 浓度增加的增色现象（在紫外光范围内），这表明 AA 和 BSA 形成了聚集体。从 BSA 和 AA 形成的聚集体的结合常数 K 约为 10(2) M(-1)，表明 AA 与 BSA 的亲和力较低。对于 BSA/AA 薄膜，还注意到 AA 的吸附过程和表面形貌结构取决于 AA 浓度。通过改变 AA 和 BSA 之间的接触时间，发现了减色现象，这与由于聚集体的形成而导致溶剂对色氨酸的可及性降低有关。此外，观察到不同形态的聚集体结构，这归因于扩散限制聚集。由于大多数药物和蛋白质相互作用的研究都是在溶液中进行的，因此使用薄膜分析这些过程可能非常有价值，因为这种系统能够在固态下采用多种研究技术。
