Measurements of Multicomponent Diffusion Coefficients for Lysozyme Chloride in Water and Aqueous Na_2SO_4

摘要

This paper presents a diffusion experimental study for ternary lysozyme-Na_2SO_4 -water system,from moderate precipitant concentrations into the supersaturated region and provides a complete set of four diffusion coefficients.These data are important in order to provide accurate models of protein diffusion with applications in growth of protein crystals for X-ray diffraction studies.All three-component mutual-diffusion experiments reported here were performed by Rayleigh interferometry at pH=4.5,T=25degC and at a mean lysozyme concentration (average of top and bottom solution concentrations) of 0.6 mM (8.6 mg/mL).Four experiments,with different combinations of protein and Na_2SO_4 concentration differences,were performed at each of five mean Na_2SO_4 concentrations (0.1,0.25,0.5,0.65 and 0.8 M),for a total of 20 experiments.In addition,it was measured dynamic light-scattering diffusion coefficients of the ternary system lysozyme chloride- Na_2SO_4 -water.