Department of Applied Chemistry, Faculty of Chemistry, Razi University, Kermanshah, Iran.
Nano drug delivery research center, Kermanshah University of medical sciences, Kermanshah, Iran.
Nucleosides Nucleotides Nucleic Acids. 2021;40(3):300-316. doi: 10.1080/15257770.2021.1872792. Epub 2021 Jan 16.
In this work the binding of artificial sweetener aspartame with human serum albumin (HSA) was studied at physiological pH. Binding studies of aspartame (APM) with HSA are useful to understand APM -HSA interaction, mechanism and providing guidance for the application and design of new and more efficient artificial sweeteners. The interaction was investigated by spectrophotometric, spectrofluorometric competition experiment and circular dichroism (CD) techniques. The results indicated that the binding of APM to HSA caused fluorescence quenching of HSA through static quenching mechanism with binding constant 1.42 × 10 M at 298 K and the number of binding sites is approximately one. Thermodynamic parameters, enthalpy changes (ΔH) and entropy changes (ΔS) were calculated to be -41.20 kJ mol and -58.19 J mol K, respectively, according to van't Hoff equation, which indicated that reaction is enthalpically driven. Quenching of the fluorescence of HSA was found to be a static quenching process. The binding constants and number of binding sites were obtained at three different temperatures (298, 308 and 318 K). Combining above results and those of spectrofluorometric competition experiment and circular dichroism (CD), indicated that APM binds to HSA via Sudlow's site I. Furthermore, the study of molecular docking on HSA binding also indicated that APM can strongly bind to the site I (subdomain IIA) of HSA mainly by hydrophobic interaction and hydrogen bond interactions exist between APM and HSA.
在这项工作中，研究了在生理 pH 下人工甜味剂阿斯巴甜与人体血清白蛋白（HSA）的结合。研究阿斯巴甜（APM）与 HSA 的结合对于理解 APM-HSA 相互作用、机制以及为新型和更有效的人工甜味剂的应用和设计提供指导具有重要意义。通过分光光度法、荧光竞争实验和圆二色性（CD）技术研究了相互作用。结果表明，APM 与 HSA 的结合通过静态猝灭机制导致 HSA 的荧光猝灭，在 298 K 时结合常数为 1.42×10 M，结合位点数约为一个。根据范特霍夫方程计算热力学参数，焓变（ΔH）和熵变（ΔS）分别为-41.20 kJ mol和-58.19 J mol K，表明反应是焓驱动的。发现 HSA 的荧光猝灭是一个静态猝灭过程。在三个不同温度（298、308 和 318 K）下获得了结合常数和结合位点数。结合上述结果以及荧光竞争实验和圆二色性（CD）的结果，表明 APM 通过 Sudlow 的位点 I 与 HSA 结合。此外，对 HSA 结合的分子对接研究也表明，APM 可以通过疏水相互作用强烈结合到 HSA 的位点 I（亚域 IIA），并且 APM 与 HSA 之间存在氢键相互作用。
