Effects of Fluorinated and Hydrogenated Surfactants on Human Serum Albumin at Different pHs

• Published in: Biomacromolecules 2006-01, Vol.7 (1), p.176-182
• Main Authors: Sabín, Juan, Prieto, Gerardo, González-Pérez, Alfredo, Ruso, Juan M, Sarmiento, Félix
• Format: Article
• Language: English
• Subjects: Applied sciences; Biological and medical sciences; Electrophoresis; Exact sciences and technology; Fluorine - chemistry; Fundamental and applied biological sciences. Psychology; Humans; Hydrogen - chemistry; Hydrogen-Ion Concentration; In solution. Condensed state. Thin layers; Molecular biophysics; Natural polymers; Physico-chemical properties of biomolecules; Physicochemistry of polymers; Proteins; Serum Albumin - chemistry; Spectrum Analysis; Surface-Active Agents - chemistry; Temperature
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/bm050549w

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 ζ-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.