%0 Journal Article
%T Physicochemical Peculiarities of Iodine-Dimethylsulfoxide-H2O Solutions and Effect on Ion Binding to Bovine Serum Albumin
%A K. Grigoryan
%A H. Shilajyan
%J Dataset Papers in Science
%D 2013
%R 10.7167/2013/534328
%X The interaction of iodine with bovine serum albumin (BSA) in dimethylsulfoxide (DMSO) aqueous solutions was studied by means of fluorescence and UV/Vis absorption spectroscopy methods. Physicochemical peculiarities of these solutions were revealed. The results showed that the tri-iodide ion formed in the 1DMSO£¿:£¿2H2O solution caused the fluorescence quenching of BSA. The modified Stern-Volmer quenching constant and corresponding thermodynamic parameters, the free energy change ( ), enthalpy change ( ), and entropy change ( ), at different temperatures (293, 298, and 303£¿K) were calculated, which indicated that the hydrophobic and electrostatic interactions were the predominant operating forces. The binding locality distance r between BSA and tri-iodide ion at different temperatures was determined based on F£¿rster nonradiation fluorescence energy transfer theory. 1. Introduction Iodine is an element that is needed for the production of the most important organoiodine compounds for human health thyroid hormones: thyroxine (T4) and triiodothyronine (T3). Without sufficient iodine, body is unable to synthesize these hormones and play a role in virtually all physiological functions. T4 is transported in blood, being protein-bound, principally to globulin, transthyretin, and serum albumin [1]. The absorption of inorganic-iodine, such as , is certainly bound to serum albumin. Serum albumins, human serum albumin (HSA), and bovine serum albumin (BSA) play an important role in the transport and disposition of a wide variety of substances like metals, fatty acids, amino acids, hormones, and drugs [2¨C6]. Competitive interactions in the aqueous solutions containing DMSO and ions were a subject of numerous studies [7, 8]. In this paper, the interaction of iodine with BSA in DMSO aqueous solutions was studied at different temperatures by using fluorescence and UV/Vis spectroscopy methods. The binding constants and the binding locality distance are calculated, and the thermodynamic parameters of the process are proposed. 2. Methodology The materials used are as follows. BSA and DMSO were purchased from Sigma Chemical Company (USA). Iodine was purified by sublimation. Doubly distilled water was used for the preparation of binary mixtures of 1DMSO£¿:£¿2H2O. BSA concentration was 0.4£¿mg/mL, determined by electron absorption spectra in the UV region using a molar absorption coefficient £¿M£¿1£¿cm£¿1 ( £¿nm) [9]. The methods applied are the following. To perform the UV/Vis absorption measurements, we apply the following. The absorption spectra of iodine in 1DMSO£¿:£¿2H2O solutions
%U http://www.hindawi.com/journals/dpis/2013/534328/