title: Spectroscopic study on binding of gentisic acid to bovine serum albumin.
abstract: The interaction of (gentisic acid) GA with (bovine serum albumin) BSA has been studied by different spectroscopic techniques. GA is a monoanionic specie at the working pH of 7.4, it was determined by combining UV-Vis absorption spectroscopy and theoretical calculations. A set of fluorescence quenching experiments at different temperatures was carried out employing the native fluorescence of BSA. A Stern-Volmer constant (KSV) of (2.07±0.12)×10(4) mol(-1) L and a binding constant (Ka) of (8.47±4.39)×10(3) were determined at 310 K. The static quenching caused by the BSA-GA complex formation seems to play a significant role in the overall quenching process. A single binding site on BSA for GA was observed. ΔH=-55.6±0.2 kJ mol(-1) and ΔS=-104.3±0.6 J mol(-1) K(-1) were determined in a set of experiments on the dependence of Ka with the temperature. The binding process is, therefore, spontaneous and enthalpy-driven. Van der Waals forces and hydrogen bonds could also play the major role in the binding mode. The secondary structure changes of BSA in the absence and presence of GA were studied by FTIR and UV-Vis absorption spectroscopy.
authors.affiliation: Departamento de Química Física, Facultad de Farmacia, Universidad de Castilla-La Mancha, Paseo de los estudiantes, s/n, 02071 Albacete, Spain. Electronic address: andres.garzon@uclm.es.
authors.forename: Andrés
authors.initials: A
authors.lastname: Garzón
authors.affiliation: Departamento de Química Física, Facultad de Farmacia, Universidad de Castilla-La Mancha, Paseo de los estudiantes, s/n, 02071 Albacete, Spain.
authors.forename: Iván
authors.initials: I
authors.lastname: Bravo
authors.affiliation: Departamento de Química Física, Facultad de Farmacia, Universidad de Castilla-La Mancha, Paseo de los estudiantes, s/n, 02071 Albacete, Spain.
authors.forename: M Rosario
authors.initials: MR
authors.lastname: Carrión-Jiménez
authors.affiliation: Instituto Botánico, Facultad de Farmacia, Universidad de Castilla-La Mancha, Paseo de los estudiantes, s/n, 02071 Albacete, Spain.
authors.forename: Ángela
authors.initials: Á
authors.lastname: Rubio-Moraga
authors.affiliation: Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Castilla-La Mancha, Avenida Camilo José Cela, 10, 13071 Ciudad Real, Spain.
authors.forename: José
authors.initials: J
authors.lastname: Albaladejo
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000737:chemistry / Q000378:metabolism*; D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D002417:Cattle; D005841:Gentisates / Q000737:chemistry / Q000378:metabolism*; D031584:Hibiscus / Q000737:chemistry; D008958:Models, Molecular; D011485:Protein Binding; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
chemical_list: D016588:Anticarcinogenic Agents; D000975:Antioxidants; D005841:Gentisates; D012710:Serum Albumin, Bovine; C010925:2,5-dihydroxybenzoic acid
keywords: Binding; Bovine serum albumin; Fluorescence quenching; Gentisic acid