DIFFUSION OF LYSOZYME CHLORIDE IN WATER AND AQUEOUS POTASSIUM CHLORIDE SOLUTIONS

The diffusion of lysozyme chloride in aqueous solution has been studied at 25°C using the Goüy interferometric technique. The concentration dependence of the diffusion coefficient in water has been measured over the concentration range 1.1599–9.1556 gem−3 and the results suggest a value of D25.W at infinite dilution of 5.838 × 10−6 cm2s−1. The variation in diffusion coefficient with ionic strength has also been considered by following the diffusion of 0.45% lysozyme chloride in a series of potassium chloride solutions. The value of D in 0.15 M KCl has been found to be approximately one quarter of that in water alone and the diffusion coefficient has been shown to increase markedly as the KCI concentration is reduced below 0.05 M. Interpretation of these observations involves consideration of solution electrostatic effects.