title: The specific binding of chlorogenic acid to human serum albumin.
abstract: Chlorogenic acid (CGA) is one of the most abundant polyphenol compounds in human diet. It is also an active component in traditional Chinese medicines which are used to treat various diseases. In this study, fluorescence spectroscopy in combination with UV-Vis absorption spectroscopy was employed to investigate the specific binding of CGA to human serum albumin (HSA) under the physiological conditions. In the mechanism discussion, it was proved that the fluorescence quenching of HSA by CGA is a result of the formation of CGA-HSA complex. Binding parameters calculating from Stern-Volmer method and Scatchard method showed that CGA bind to HSA with the binding affinities of the order 10(4) l mol(-1). The thermodynamic parameters studies revealed that the binding was characterized by negative enthalpy and positive entropy changes and the electrostatic interactions play a major role for CGA-HSA association. Site marker competitive displacement experiments demonstrated that CGA specific bind to site I (subdomain IIA) of HSA. The binding distance r (3.10 nm) between donor (Trp-214) and acceptor (CGA) was obtained according to fluorescence resonance energy transfer. Furthermore, the effect of metal ions on CGA-HSA system was studied.
authors.affiliation: Hubei Key Laboratory of Pollutant Analysis & Reuse Technology, Department of Chemistry, Hubei Normal University, Huangshi, 435002 Hubei, People's Republic of China. yjhu@263.net
authors.forename: Yan-Jun
authors.initials: YJ
authors.lastname: Hu
authors.forename: Chao-Hui
authors.initials: CH
authors.lastname: Chen
authors.forename: Shu
authors.initials: S
authors.lastname: Zhou
authors.forename: Ai-Min
authors.initials: AM
authors.lastname: Bai
authors.forename: Yu
authors.initials: Y
authors.lastname: Ou-Yang
mesh_terms: D002726:Chlorogenic Acid / Q000378:metabolism*; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D046912:Multiprotein Complexes / Q000378:metabolism*; D011485:Protein Binding; D012709:Serum Albumin / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D055672:Static Electricity; D013816:Thermodynamics; D056928:X-Ray Absorption Spectroscopy
chemical_list: D046912:Multiprotein Complexes; D012709:Serum Albumin; D002726:Chlorogenic Acid