The Interaction of Bovine Serum Albumin with Surfactants Studied by Light Scattering

Abstract

The interaction between bovine serum albumin (BSA) and several surfactants has been investigated by light scattering. Anionic (sodium dodecyl sulfate, SDS), cationic (dodecyl trimethylammonium bromide, DTAB), and nonionic (polyoxyethylene 8 lauryl ether, C12E8) surfactants, all containing a C12 alkyl chain, were used to study the effect of different headgroups on the complex formation. The hydrodynamic radii of the complexes obtained by dynamic light scattering indicate that cooperative binding of DTAB occurs at higher surfactant concentrations than in comparative solutions of SDS and C12E8. The effect of chain length is shown for the cationic surfactants DTAB and cetyl trimethylammonium bromide (CTAB, C16 alkyl chain). The higher surface activity of CTAB results in complex formation at a lower surfactant concentration compared to DTAB. The hydrodynamic radii of the BSA−SDS and BSA−DTAB complexes at saturation were determined as ∼5.9 nm and ∼4.8 nm, respectively. The hydrodynamic radius of the reduced BSA−SDS complex is somewhat smaller than the corresponding native BSA−SDS complex. Static light scattering (SLS) measurements were performed on BSA−SDS systems to determine the number of BSA molecules in the complex. Prior to SLS measurements the BSA−SDS solutions were dialyzed against a large volume of SDS solution in order to determine the refractive index increment ∂n/∂c BSA at constant chemical potential. It was observed that a very long dialysis time (several weeks) was needed to reach equilibrium. Measurements on solutions that had not reached equilibrium resulted in improbably high values of the number of BSA molecules in the complex.

Photocontrol of Protein Folding: The Interaction of Photosensitive Surfactants with Bovine Serum Albumin

“…ethylammonium bromide (DTAB) concentrations with DLS (49,52), with the maximum hydrodynamic radius measured in Figure 2 consistent with observed values from these studies. Furthermore, as the hydrophobicity of traditional surfactants is increased through the use of longer hydrocarbon tails, BSA structural changes have been observed to occur at lower surfactant concentrations (29), analogous to a greater degree of unfolding for the more hydrophobic trans form of azoTAB.…”

The interaction between poly(vinylpyrrolidone) and reversed micelles of water/AOT/ n -heptane

“…Light scattering is a widely known experimental tool used to investigate the interaction between polymers and surfactants because it is sensitive to the existence of large complexes [24,31,32]. Figure 3 shows the dependence of the hydrodynamic radius (R h ) of the reversed micelle on x 0 in the presence of different concentrations of PVP-K30.…”

Interaction of bovine serum albumi with two alkylimidazolium-based ionic liquids investigated by microcalorimetry and circular dichroism

“…To use them correctly, it is necessary to have an idea of how and in which amounts they interact with proteins. Although surfactant-protein interactions have been widely studied for half a century [1][2][3][4][5], the mechanism of interaction is not well understood. Knowledge of the interactions is not only fundamental in theoretics, but also practical in industrial applications.…”