The Interaction Between Human Immunoglobulin G and Sodium Perfluorooctanoate in Aqueous Solutions

PAULA V. MESSINA ; GERARDO PRIETO; JUAN SABIN; ELENA BLANCO; CARLA VARELA; VERÓNICA DODERO; JUAN RUSO; FÉLIX SARMIENTO

Manchester

Conferencia; 6th International Conference on Polymer-Solvent Complexes and Intercalates; 2006

School of Chemical Engineering and Analytical Science. University of Manchester

As a continuation of our previous work on the interaction of blood proteins with surfactants, here we present a wide study of the interaction between the second major soluble protein constituent of the circulatory system, immunoglobulin G (IgG), and perfluorinated surfactant sodium perfluorooctanote (SPFO). A combination of UV-vis, UV-CD spectroscopic methods, electrophoretic mobility measurements and ion-selective electrodes were used as physical techniques. The application of SPFO selective electrodes determined that there were true specific unions between surfactant molecules and the IgG structure. This fact suggests the binding of surfactant hydrophobic fluorinated tails, which will penetrate into hydrophobic domains of the globular IgG in order to reduce their contacts with water. The experimental data are presented as Klotz and Scatchard plots and analysed on the empirical Hill equation. The results show that SPFO manifests a high affinity for IgG. The surfactant binding produces conformational changes in IgG, which were well characterized by UV-vis and UV-CD spectroscopy. Chemical and thermal unfolding was analysed and the thermodynamic parameters were determined.