title: Fluorometric investigation of the interaction between methylene blue and human serum albumin.
abstract: The interaction between methylene blue (MB) and human serum albumin (HSA) was investigated by fluorescence spectroscopy and UV-vis absorbance spectroscopy. In the mechanism discussion, it was proved that the fluorescence quenching of HSA by MB is a result of the formation of MB-HSA complex and electrostatic interactions play a major role in stabilizing the complex. The Stern-Volmer quenching constant K(SV) and corresponding thermodynamic parameters DeltaH, DeltaG and DeltaS were calculated. Binding studies concerning the number of binding sites n and apparent binding constant Kb were performed by fluorescence quenching method. The distance r between the donor (HSA) and the acceptor (MB) was obtained according to fluorescence resonance energy transfer (FRET). Wavelength shifts in synchronous fluorescence spectra showed the conformation of HSA molecules is changed in the presence of MB.
authors.affiliation: Department of Chemistry, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, PR China.
authors.forename: Yan-Jun
authors.initials: YJ
authors.lastname: Hu
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.forename: Jia-Xin
authors.initials: JX
authors.lastname: Dong
authors.forename: Song-Sheng
authors.initials: SS
authors.lastname: Qu
mesh_terms: D001665:Binding Sites; D004347:Drug Interactions; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D007700:Kinetics; D008751:Methylene Blue / Q000032:analysis*; D008956:Models, Chemical; D008968:Molecular Conformation; D011485:Protein Binding; D012709:Serum Albumin / Q000032:analysis*; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D013816:Thermodynamics; D014364:Tryptophan / Q000737:chemistry; D014466:Ultraviolet Rays
chemical_list: D012709:Serum Albumin; D014364:Tryptophan; D008751:Methylene Blue