25] Gel filtration

Abstract

Publisher Summary Gel filtration is performed using porous beads as the chromatographic support. A column constructed from such beads has two measurable liquid volumes—the external volume, consisting of the liquid between the beads and the internal volume, consisting of the liquid within the pores of the beads. The large protein molecules are excluded from the internal volume and are emerged first from the column while the smaller protein molecules, which can access the internal volume, emerge later. If all the proteins in a mixture are known, or can be assumed to have the same shape, then the order of elution will be the inverse of their molecular weights. Fewer than 10 proteins can be resolved from one another in the effluent from any size exclusion column. This relatively low resolution occurs because none of the proteins is retained by the column during chromatography and because non-ideal flow occurs around the beads.