title: Effect of glycerol and dimethyl sulfoxide on the phase behavior of lysozyme: theory and experiments.
abstract: Salt, glycerol, and dimethyl sulfoxide (DMSO) are used to modify the properties of protein solutions. We experimentally determined the effect of these additives on the phase behavior of lysozyme solutions. Upon the addition of glycerol and DMSO, the fluid-solid transition and the gas-liquid coexistence curve (binodal) shift to lower temperatures and the gap between them increases. The experimentally observed trends are consistent with our theoretical predictions based on the thermodynamic perturbation theory and the Derjaguin-Landau-Verwey-Overbeek model for the lysozyme-lysozyme pair interactions. The values of the parameters describing the interactions, namely the refractive indices, dielectric constants, Hamaker constant and cut-off length, are extracted from literature or are experimentally determined by independent experiments, including static light scattering, to determine the second virial coefficient. We observe that both, glycerol and DMSO, render the potential more repulsive, while sodium chloride reduces the repulsion.
authors.affiliation: Max-Planck-Institut für Dynamik und Selbstorganisation, Am Faßberg 17, 37077 Göttingen, Germany. christoph.goegelein@ds.mpg.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Gögelein
authors.forename: Dana
authors.initials: D
authors.lastname: Wagner
authors.forename: Frédéric
authors.initials: F
authors.lastname: Cardinaux
authors.forename: Gerhard
authors.initials: G
authors.lastname: Nägele
authors.forename: Stefan U
authors.initials: SU
authors.lastname: Egelhaaf
mesh_terms: D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D005990:Glycerol / Q000737:chemistry*; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D011789:Quantum Theory; D012965:Sodium Chloride / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D012965:Sodium Chloride; D009113:Muramidase; D005990:Glycerol; D004121:Dimethyl Sulfoxide