Affiliations: Experimental Center for Life Sciences, School of Life Sciences, Shanghai University, Shanghai, China | College of Sciences, Shanghai University, Shanghai, China | Department of Biomedical Engineering, University of Southern California, Los Angeles, USA
Note: [] Corresponding author: Xu Chen, Experimental Center for Life Sciences, School of Life Sciences, Shanghai University, 99 Shang Da Road, Shanghai, 200444, China. Tel.: +86 21 66134592 205; Fax: +86 21 66134845; E-mails: xuchen@ staff.shu.edu.cn, yschenxu@sina.com.
Abstract: The interaction between loureirin B (Lour B) and human serum albumin (HSA) was investigated by fluorescence and UV–vis absorption spectroscopy. Experimental results indicated that loureirin B had a strong ability to quench the intrinsic fluorescence of HSA through a dynamic quenching procedure. The fluorescence quenching data revealed that the quenching constants (KSV) 2.68×104, 3.30×104 and 4.10×104 l/mol at 300, 310 and 320 K, respectively. Based on the thermodynamic parameters obtained, the positive values of enthalpy change ΔH and entropy change ΔS suggested that hydrophobic forces played a major role in the interaction of Lour B with HSA. According to Förster theory of energy transfer, the distance r between HSA and Lour B was calculated to be 2.85 nm. Furthermore, the effect of Lour B on the conformation of HSA was analyzed by synchronous fluorescence and three-dimensional fluorescence spectra.
