Study on the interaction between theasinesin and human serum albumin by fluorescence spectroscopy

• Published in: Journal of luminescence Vol. 130; no. 1; pp. 168 - 173
• Main Authors: Ge, Feng, Chen, Chaoyin, Liu, Diqiu, Han, Benyong, Xiong, Xiangfeng, Zhao, Shenglan
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 2010; Elsevier
• Subjects: Absorption spectra; Biological and medical sciences; Fluorescence quenching; Fundamental and applied biological sciences. Psychology; Human serum albumin; Interactions. Associations; Intermolecular phenomena; Molecular biophysics; Theasinesin; Thermodynamic parameter; Human serum albumin; Theasinesin; 87.64.Ni; 87.15.Kg; Thermodynamic parameter; Absorption spectra; 32.50.+d; Fluorescence quenching; Human; Catechin; Electrostatic interaction; Fluorescence; Serum albumin; Conformational changes; Absorption spectrum; Thermodynamic model; Luminescence quenching; Ultraviolet visible spectrum; Energy transfer; 87.64.Ni Theasinesin
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2009.08.003

The binding properties on theasinesin to human serum albumin (HSA) have been studied for the first time using fluorescence spectroscopy in combination with UV–vis absorbance spectroscopy. The results showed that theasinesin strongly quenched the intrinsic fluorescence of HSA through a static quenching procedure, and non-radiation energy transfer happened within molecules. The number of binding site was 1, and the efficiency of Förster energy transfer provided a distance of 4.64 nm between tryptophan and theasinesin binding site. At 298, 310 and 323 K, the quenching constants of HSA–theasinesin system were 2.55×10 3, 2.16×10 3 and 1.75×10 3 mol L −1. Δ H θ , Δ S θ and Δ G θ were obtained based on the quenching constants and thermodynamic theory (Δ H θ <0, Δ S θ >0 and Δ G θ <0). These results indicated that hydrophobic and electrostatic interactions are the mainly binding forces in the theasinesin–HSA system. In addition, the results obtained from synchronous fluorescence spectra showed that the binding of theasinesin with HSA could induce conformational changes in HSA.