Determination of protein diffusion coefficients in agarose gel with a diffusion cell

A diffusion cell has been used to measure the effective diffusion coefficients of proteins. The method is applied to lysozyme and BSA at different pH and ionic strength. A parameter optimization technique is used to estimate the diffusion coefficients directly from experimental data. The importance and influence of pH and ionic strength on the diffusive properties in an agarose gel have been demonstrated. A comparison with other methods showed that there is good agreement. The diffusion cell is an accurate and easy-to-use method for the measurement of protein diffusion coefficients, in spite of the long time required for a protein diffusion experiment. For smaller proteins this time can be shortened considerably by the present parameter optimization technique. (C) 2003 Elsevier B.V. All rights reserved.