title: Interaction of isofraxidin with human serum albumin.
abstract: This study was designed to examine the interaction of isofraxidin with human serum albumin (HSA) under physiological conditions with drug concentrations in the range of 3.3 x 10(-6) mol L(-1)-3.0x10(-5) mol L(-1) and HSA concentration at 1.5 x 10(-6) mol L(-1). Fluorescence quenching methods in combination with Fourier transform infrared (FT-IR) spectroscopy and circular dichroism (CD) spectroscopy were used to determine the drug-binding mode, the binding constant and the protein structure changes in the presence of isofraxidin in aqueous solution. Spectroscopic evidence showed that the interaction results in one type of isofraxidin-HSA complex with binding constants of 4.1266 x 10(5) L mol(-1), 3.8612 x 10(5) L mol(-1), 3.5063 x 10(5) L mol(-1), 3.1241 x 10(5) L mol(-1) at 296 K, 303 K, 310 K, 318 K, respectively. The thermodynamic parameters, enthalpy change (DeltaH) and entropy change (DeltaS) were calculated to be -10.08 kJ mol(-1) and 73.57 J mol(-1) K(-1) according to van't Hoff equation, which indicated that hydrophobic interaction played a main role in the binding of isofraxidin to HSA. The experiment results are nearly in accordance with the calculation results obtained by Silicon Graphics Ocatane2 workstation.
authors.affiliation: Department of Chemistry, Lanzhou University, Lanzhou 730000, China.
authors.forename: Jiaqin
authors.initials: J
authors.lastname: Liu
authors.forename: Jianniao
authors.initials: J
authors.lastname: Tian
authors.forename: Xuan
authors.initials: X
authors.lastname: Tian
authors.forename: Zhide
authors.initials: Z
authors.lastname: Hu
authors.forename: Xingguo
authors.initials: X
authors.lastname: Chen
mesh_terms: D002942:Circular Dichroism; D003374:Coumarins / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D008968:Molecular Conformation; D012709:Serum Albumin / Q000737:chemistry* / Q000378:metabolism*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
chemical_list: D003374:Coumarins; D012709:Serum Albumin; C008182:isofraxidin