Diffusivity, viscosity, and cluster formation in protein solutions

The diffusion coefficient and viscosity of lysozyme solutions were measured at 25°C in various buffers with and without sodium chloride. Measurements were made over the entire concentration range in each case and were extended into the supersaturated region. The results show that diffusion coefficient behavior depends strongly on the buffer used and the ionic strength of the solution, which means the amount of sodium chloride used in buffer solution. Viscosity measurements indicate a small degree of time dependence, with the viscosity increasing with solution age.