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摘要
Bis(2-ethylhexyl)phthalate (DEHP) is one of the biggest selling synthetic plasticizers which can migrate to environment and enter human body via air, water, medical apparatus, and food. In this paper, three-dimensional fluorescence (3D-FL) spectroscopy, UV-visible absorption spectroscopy and circular dichroism (CD) spectroscopy were employed to explore the binding of DEHP to bovine serum albumin (BSA) at the physiological conditions. The number of binding sites n and observed binding constant K (b) was measured by fluorescence quenching method. It was found that the fluorescence quenching was static quenching mechanism and caused by the formation of DEHP-BSA complex at ground state. The enthalpy change (Delta H (theta)), Gibbs free energy change (Delta G (theta)) and entropy change (Delta S (theta)) were calculated at four different temperatures. Site marker competitive displacement experiments were carried out to identify the binding location. The results demonstrated that DEHP bound primarily on Sudlow's site I in domain IIA of BSA molecule. The distance r (2.95 nm) between donor (BSA) and acceptor (DEHP) was obtained based on Forster's non-radiation fluorescence resonance energy transfer (FRET) theory. Furthermore, the CD spectral results indicated that the secondary structure of BSA changed in presence of high concentration of DEHP, which implied that high level of DEHP in plasma was potentially poisonous. The study is helpful to evaluating the health risk of DEHP and understanding its functional effects on protein during the blood transportation process.
- 出版日期2012-12
- 单位荆楚理工学院
