Effects of fluorinated and hydrogenated surfactants on human serum albumin at different pHs.
Complexation between human serum albumin (HSA) and two different surfactants, one fully fluorinated (sodium perfluorooctanoate, SPFO) and one fully hydrogenated (sodium caprylate, SO), was studied using zeta-potential measurements and difference spectroscopy. The study was carried out at three different pHs, 3.2, 6.7, and 10.0. The spectroscopy study was performed at pHs 6.7 and 10.0, given that at pH 3.2 high turbidity was observed in the wide range of surfactant concentrations. The results were interpreted in terms of the electrostatic and hydrophobic contributions to the stability of the different phases formed in the water-surfactant-HSA system. Solutions and precipitates were observed in the concentration range investigated in more detail. Using Pace methods, the thermodynamic values of the surfactant-induced conformational changes in HSA were determined for sodium perfluorooctanoate in the concentration range 2-12 mmol dm(-3) at pH 6.7 and 5-22 mmol dm(-3) at pH 10.0. Electrophoretic measurements were used to characterize surfactant adsorption by determining the number of molecules adsorbed on the surface of HSA and the Gibbs energy of adsorption. Finally, the interactions between human serum albumin and other anionic surfactants studied by other authors were compared with those observed in the present work.
Sabín
Juan
J
Biophysics and Interfaces Group, Department of Applied Physics, Faculty of Physics, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Prieto
Gerardo
G
González-Pérez
Alfredo
A
Ruso
Juan M
JM
Sarmiento
Félix
F
D004586:Electrophoresis; D005461:Fluorine / Q000737:chemistry*; D006801:Humans; D006859:Hydrogen / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D012709:Serum Albumin / Q000737:chemistry*; D013057:Spectrum Analysis; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature
D012709:Serum Albumin; D013501:Surface-Active Agents; D005461:Fluorine; D006859:Hydrogen