Phase Behavior and Phase Structure of Protein–Surfactant–Water Systems

Conformational polymorphism, stability and aggregation in spider dragline silks proteins

“…Phase behavior studies [38] have shown that protein and surfactants oppositely charged give rise, successively with increasing surfactants concentration, to the formation of a solution, a precipitate and a gel, and finally, to the re-dissolution of precipitate/gel to a large solution phase [39,40]. However, protein and surfactants of similar charge often present no precipitate [38]. The general picture emerging from these studies is that the surfactant molecules interact with the polymers/proteins at a critical aggregation concentration forming micellar clusters along the polymer chains [37].…”

Interactions of Ovalbumin with Ionic Surfactants

“…25,26 The phasegrams of the oppositely charged OVA-DOTAC (dodecyltrimethylammonium chloride) system and the similarly charged OVA-SDS system show that there are three main regions (precipitate, gel and colorless solution) in the former case and there is only one colorless solution region in the latter one. 25,26 Daniel et al 27 have fundamentally investigated the protein partitioning in the two-phase aqueous mixed (nonionic/ionic) micellar systems. All the above studies widen the range of the researches of the interactions of the protein with surfactants, but not enough to understand the structures of the colorless solution in the OVA/surfactant phasegrams, the optical properties of OVA, and the role of the hydrophobic interaction and the electrostatic interaction between OVA and surfactant.…”

“…25,26 Some researchers have studied the structures and stabilities of OVAsurfactant aggregates by measuring their phase behavior and observing their images with a transmission electron microscope (TEM). 25,26 The phasegrams of the oppositely charged OVA-DOTAC (dodecyltrimethylammonium chloride) system and the similarly charged OVA-SDS system show that there are three main regions (precipitate, gel and colorless solution) in the former case and there is only one colorless solution region in the latter one. 25,26 Daniel et al 27 have fundamentally investigated the protein partitioning in the two-phase aqueous mixed (nonionic/ionic) micellar systems.…”

Small-angle X-ray scattering and electron paramagnetic resonance study of the interaction of bovine serum albumin with ionic surfactants

“…The protein denaturation is believed to occur at these concentrations. Several techniques have been used to investigate the assembled protein-surfactant complexes: UV-vis absorption [10], fluorescence and circular dichroism [7,[10][11][12][13], small-angle neutron scattering (SANS) [14,15], small-angle X-ray scattering (SAXS) [16,17], light scattering [18,19], cryogenic transmission electron microscopy and 2 H NMR relaxation rates [20,21], and other physicochemical techniques such as tensiometric and viscosimetric measurements [22], isothermal titration calorimetry and FTIR [23], and differential scanning calorimetry [24]. At high surfactant concentrations a variety of models have been proposed, the "pearl necklace" model being the most discussed in the literature [7][8][9].…”