I have a serious problem with the resolution of my gelfiltration column. I am trying to purify a cytosolic protein complex from arabidopsis thalianaof about 130-160 kDa. In the moment I prepurify the protein by a combination of a weak anion exchanger (DE52) and a hydrophobic interactionchromatography using octylsepharose. After this steps I load my protein suspension on a combined gelfiltration column (Sephadex S-200 / S-300). My problem is now, that the resolution of the gelfiltration between 100 and 300 kDa is very weak. Maybe some of you have ideas how to manage this problem, probably you have expirience with different column materials with a higherresolution between 100 and 200 kDa.