Sodium benzoate (SB) is widely used as a preservative in food industry, and bovine serum albumin (BSA) is a major carrier protein similar to human serum albumin (HSA), the study of the binding between the two has great significance on human health. In this paper, we systematically investigated the binding of SB and BSA under the simulated physiological conditions combining with various common analytical methods, e.g., fluorescence, UV–vis absorption, synchronous fluorescence and circular dichroism (CD) spectra, as well as molecular docking method. The fluorescence quenching measurements were respectively carried out at 298 K, 303 K and 308 K using the Stern–Volmer method. The results reveal that ground state SB–BSA complex was formed within the binding constants from 2.02 × 104 to 7.9 × 103 M−1. Meanwhile, the negative values of ΔH0 (− 43.92 kJ mol−1) and ΔS0 (− 111.6 J mol−1 K−1) demonstrated that both the hydrogen binding interaction and van der Waals forces contributed to stabilizing the SB–BSA complex. The site marker competitive experiments show that the SB and BSA bound at site I. Furthermore, the experimental results of UV–vis absorption, synchronous fluorescence and CD spectra indicate that the binding of SB and BSA may change the conformation of BSA. In addition, the molecular docking experiment suggests that hydrogen bond was formed in the interaction between SB and BSA.

中文翻译：

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苯甲酸钠食品添加剂与牛血清白蛋白的结合相互作用：多光谱和分子对接研究

苯甲酸钠(SB)在食品工业中广泛用作防腐剂，而牛血清白蛋白(BSA)是类似于人血清白蛋白(HSA)的主要载体蛋白，研究两者的结合对人类健康具有重要意义。本文结合荧光、紫外可见吸收、同步荧光和圆二色性（CD）光谱等常用分析方法以及分子对接方法，系统研究了模拟生理条件下SB和BSA的结合情况。 。使用 Stern-Volmer 方法分别在 298 K、303 K 和 308 K 下进行荧光猝灭测量。结果表明，基态 SB-BSA 复合物是在 2.02 × 104 至 7.9 × 103 M−1 的结合常数范围内形成的。同时，ΔH0 (− 43.92 kJ mol−1) 和 ΔS0 (− 111.6 J mol−1 K−1) 的负值表明氢键相互作用和范德华力都有助于稳定 SB-BSA 复合物。位点标记竞争实验表明SB和BSA在位点I处结合。此外，紫外可见吸收、同步荧光和CD光谱的实验结果表明SB和BSA的结合可能改变BSA的构象。此外，分子对接实验表明SB与BSA之间的相互作用形成了氢键。