title: Spectroscopic investigation on the interaction of 3,7-dihydroxyflavone with different isomers of human serum albumin.
abstract: The interaction mechanism of 3,7-dihydroxyflavone (3,7-diHF) and human serum albumin (HSA) was investigated by fluorescence quenching, fluorescence enhancement, steady-state and time-resolved fluorescence emission and UV-vis absorption spectrometry. The binding site of 3,7-diHF on protein was determined by investigating the spectroscopic properties of 3,7-diHF-HSA complex at pH 7.4 and pH 3.5 individually, and confirmed by the site marker competitive experiments. The binding parameters of 3,7-diHF-HSA complex were estimated by fluorescence quenching experiments, and the data were in good agreement with the results obtained from fluorescence enhancement measurements. A remarkable increase in the fluorescence anisotropy values suggested that 3,7-diHF bound at a motional restricted pocket on HSA. The results indicated that 3,7-diHF, in anionic form, was bound within the hydrophobic pockets of the subdomain IIA of HSA (site I), and stabilised mainly by electrostatic force and ionic interactions. The binding mode of drug-protein was discussed based on above experimental results.
authors.affiliation: Analytical & Testing Center of Beijing Normal University, Beijing 100875, PR China.
authors.forename: Ji
authors.initials: J
authors.lastname: Ma
authors.affiliation: Analytical & Testing Center of Beijing Normal University, Beijing 100875, PR China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Analytical & Testing Center of Beijing Normal University, Beijing 100875, PR China.
authors.forename: Luan
authors.initials: L
authors.lastname: Chen
authors.affiliation: Analytical & Testing Center of Beijing Normal University, Beijing 100875, PR China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Xie
authors.affiliation: Analytical & Testing Center of Beijing Normal University, Beijing 100875, PR China.
authors.forename: Li-Yun
authors.initials: LY
authors.lastname: Wang
authors.affiliation: Analytical & Testing Center of Beijing Normal University, Beijing 100875, PR China. Electronic address: xiemx@bnu.edu.cn.
authors.forename: Meng-Xia
authors.initials: MX
authors.lastname: Xie
mesh_terms: D001665:Binding Sites; D005419:Flavonoids / Q000737:chemistry*; D006801:Humans; D007536:Isomerism; D008958:Models, Molecular; D012709:Serum Albumin / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D005419:Flavonoids; D012709:Serum Albumin; C422925:3,7-dihydroxyflavone
keywords: Absorption spectra; Flavonol; Fluorescence; Isomers of HSA