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Protein-protein and protein-salt interactions have been obtained for ovalbumin in solutions of ammonium sulfate and for lysozyme in solutions of ammonium sulfate, sodium chloride, potassium isothiocyanate, and potassium chloride. The two-body interactions between ovalbumin molecules in concentrated ammonium-sulfate solutions can be described by the DLVO(More)
How colloidal particles interact with each other is one of the key issues that determines our ability to interpret experimental results for phase transitions in colloidal dispersions and our ability to apply colloid science to various industrial processes. The long-accepted theories for answering this question have been challenged by results from recent(More)
The diffusion of hen egg-white lysozyme has been studied by dynamic light scattering in aqueous solutions of ammonium sulfate as a function of protein concentration to 30 g/liter. Experiments were conducted under the following conditions: pH 4-7 and ionic strength 0.05-5.0 M. Diffusivity data for ionic strengths up to 0.5 M were interpreted in the context(More)
Protein-protein interactions were measured for ovalbumin and for lysozyme in aqueous salt solutions. Protein-protein interactions are correlated with a proposed potential of mean force equal to the free energy to desolvate the protein surface that is made inaccessible to the solvent due to the protein-protein interaction. This energy is calculated from the(More)
Protein-protein interactions have been measured for a mutant (D101F) lysozyme and for native lysozyme in concentrated solutions of ammonium sulfate at pH 7 and sodium chloride at pH 4.5. In the mutant lysozyme, a surface aspartate residue has been replaced with a hydrophobic phenylalanine residue. The protein-protein interactions of D101F lysozyme are more(More)
Due to the interplay of Coulombic repulsion and attractive dipolar and van der Waals interactions, solutions of globular proteins display a rich variety of phase behavior featuring fluid-fluid and fluid-solid transitions that strongly depend on solution pH and salt concentration. Using a simple model for charge, dispersion and dipole-related contributions(More)
The interactions of partially unfolded proteins provide insight into protein folding and protein aggregation. In this work, we studied partially unfolded hen egg lysozyme interactions in solutions containing up to 7 M guanidinium chloride (GdnHCl). The osmotic second virial coefficient (B(22)) of lysozyme was measured using static light scattering in GdnHCl(More)
Understanding aqueous protein-protein interactions is crucial for the development of a molecular-thermodynamic model for salt-induced protein precipitation. In addition, protein interactions are important in many disease states, including cataract formation and alpha-amyloid diseases. Fluorescence anisotropy provides a means to measure intermolecular(More)
Ionic liquids (ILs) are promising solvents for the pretreatment of biomass as certain ILs are able to completely solubilize lignocellulose. The cellulose can readily be precipitated with an anti-solvent for further hydrolysis to glucose, but the anti-solvent must be removed for the IL to be recovered and recycled. We describe the use of aqueous kosmotropic(More)
Protein aggregation is a challenge to the successful manufacture of protein therapeutics; it can impose severe limitations on purification yields and compromise formulation stability. Advances in computer power, and the wealth of computational studies pertaining to protein folding, have facilitated the development of molecular simulation as a tool to(More)