CLUSTERING PHENOMENON AND GROWTH UNITS IN LYSOZYME AQUEOUS-SOLUTION AS REVEALED BY LASER-LIGHT SCATTERING METHOD

To analyse the clustering phenomenon, the diffusion coefficient in and the viscosity of the bulk supersaturated solutions were measured using quasi-elastic light scattering, and the concentration gradient in the diffusion boundary layer around a growing crystal interface was measured by means of Mach-Zehnder interferometry. The results obtained in case of tetragonal lysozyme crystals have demonstrated that (1) the solute particle size determined from values of both the diffusion coefficient and the viscosity indicated the presence of the solute clustering in the bulk supersaturated solutions, but (2) the major growth units controlling the growth rate were monomolecular entities. The growth kinetics for tetragonal lysozyme crystals were also analysed, based on the surface microtropographic observations, and it was shown that the growth was principally controlled by the surface kinetic process.