Gel chromatography on a Sepharose 4B column: earlier elution of protein-sodium dodecyl sulfate complexes of low Stokes radii.

A procedure is described for the determination of the Stokes radius of a detergent micelle by gel chromatography. It was observed that different lots of Sepharose 4B can exhibit a wide variation in the permeation of their gel pores. It is shown that this variation is due to differences in their pore size distribution. It has been observed that protein-sodium dodecyl sulfate (SDS) complexes of high Stokes radii eluted on a Sepharose 4B column with Stokes radii lower than the theoretical, as it has been previously reported but that protein-SDS complexes of low Stokes radii (less than 70 A), contrary to what might have been expected, eluted with Stokes radii higher than the theoretical. Evidence was obtained that their anomalous elution is due to an interaction of the detergent SDS with the gel pores of small diameter.