title: Thermodynamic analysis of thymoquinone binding to human serum albumin.
abstract: The interaction of thymoquinone (TQ) with human serum albumin (HAS) in physiological buffer (pH=7.0) was studied at four temperatures in the range 25-50 °C using fluorescence quenching study. The binding parameters were determined by Scatchard and Stern-Volmer models. Fluorescence quenching data revealed that the binding constants (Ksc) are 1.71×10(4), 1.08×10(4), 1.03×10(4) and 0.969×10(4) M(-1) at 298, 303, 313 and 323 K, respectively (on the basis of Scatchard model). The thermodynamic parameters ΔG°, ΔH° and ΔS° were calculated the results indicated that the hydrogen bonding and hydrophobic interactions were the predominant intermolecular factors in stabilizing the TQ-HSA complex. The distance between donor (HSA) and acceptor (TQ) was calculated to be 3.26 nm based on Förster's non-radiative energy transfer theory.
authors.affiliation: Chemistry department, Faculty of Science, Islamic University of Gaza, Palestine. Electronic address: zyasseen@iugaza.edu.ps.
authors.forename: Zeyad J
authors.initials: ZJ
authors.lastname: Yasseen
authors.affiliation: Faculty of Medicine, Islamic University of Gaza, Palestine.
authors.forename: Jehad H
authors.initials: JH
authors.lastname: Hammad
authors.affiliation: Chemistry department, Faculty of Science, Islamic University of Gaza, Palestine.
authors.forename: Hussein A
authors.initials: HA
authors.lastname: ALTalla
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D016227:Benzoquinones / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008958:Models, Molecular; D011485:Protein Binding; D012709:Serum Albumin / Q000737:chemistry / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics
chemical_list: D000596:Amino Acids; D016227:Benzoquinones; D012709:Serum Albumin; C003466:thymoquinone
keywords: Fluorescence; Human serum albumin; Thermodynamic analysis; Thymoquinone