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problem with loading the protein on to SDS-Gel - (Oct/18/2011 )


I am purifying a protein by SP-sepharose cation exchange column. The buffer i use to elute the protein contains potassium chloride in it. Therefore as soon as i add 4X SDS dye to my sample, it precipitates and on heating it becomes sticky and gelatinous. I need to run the protein on the gel to check where my protein is eluted. I cannot load because its too sticky and it wont run on the gel. Any suggestions?


1. Can't you use sodium chloride or lithium chloride for elution?
2. You could try buffer exchange with dialysis, ultrafiltration or gel filtration (eg. PD-10 columns).