College of Environmental Science and Engineering, Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Gongshang University, Hangzhou Zhejiang 310012, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2013 Mar;104:377-82. doi: 10.1016/j.saa.2012.11.087. Epub 2012 Dec 5.
The binding of three imidazolium chloride ionic liquids (ILs) with bovine serum albumin (BSA) were investigated by UV absorption spectra, fluorescence spectra and synchronous fluorescence spectra. The results showed that the UV absorption of the BSA was red-shift, and intensity of UV absorption declined with the increase in concentration of ILs. According to fluorescence spectra, fluorescence quenching of the BSA was happened with ILs added, and the main reason is static quenching. The study of synchronous fluorescence spectra indicated that ILs interacted with tryptophan (Trp) and tyrosine (Tyr) residues, changed the structure and the internal hydrophobic conformation of BSA. The binding constant K and the numbers of binding sites n were obtained by Stern-Volmer equation. For [Bmim]Cl, K=16.12 L mol(-1), n was 0.64; for [Hmim]Cl, K=31.48 L mol(-1), n was 0.70; for [Omim]Cl, K=355.22 L mol(-1), n was 0.99. The binding strength of ILs with BSA is expected to show the trend with the length of carbon chain, [Bmim]Cl<[Hmim]Cl<[Omim]Cl.
采用紫外吸收光谱、荧光光谱和同步荧光光谱法研究了三种氯化咪唑离子液体（ILs）与牛血清白蛋白（BSA）的结合情况。结果表明，BSA 的紫外吸收发生红移，随着 ILs 浓度的增加，紫外吸收强度下降。根据荧光光谱，加入 ILs 后 BSA 的荧光发生猝灭，主要原因是静态猝灭。同步荧光光谱研究表明，ILs 与色氨酸（Trp）和酪氨酸（Tyr）残基相互作用，改变了 BSA 的结构和内部疏水性构象。通过 Stern-Volmer 方程得到结合常数 K 和结合位点数 n。对于 [Bmim]Cl，K=16.12 L mol(-1)，n 为 0.64；对于 [Hmim]Cl，K=31.48 L mol(-1)，n 为 0.70；对于 [Omim]Cl，K=355.22 L mol(-1)，n 为 0.99。ILs 与 BSA 的结合强度有望表现出与碳链长度的趋势，[Bmim]Cl<[Hmim]Cl<[Omim]Cl。
