Diffusion of proteins in Sepharose Cl-B gels

The reduced diffusion coefficient, D/D0, of fluorescein-labelled globular proteins in the agarose gels Sepharose Cl-2B, 4B and 6B were measured by the FRAP method. Comparison of the partition coefficients of the native and the labelled proteins in the gel showed that the fluorescein residues did not introduce new interactions between the solute and the gel matrix. D/D0 decreased as a function of the Stokes radius. The variation of D/D0 as a function of the partition coefficient of the proteins in the gel did not agree with a previously published prediction. This is in contrast with the diffusion of globular proteins in ACA34 gel, in which the sieving matrix is made of cross-linked polyacrylamide.