How do I get rid of this contaminant? - His-tagged protein eluted with 300mM imidazole (Aug/17/2009 )
I don't think it was contaminant.... It was an artefact...
i am facing the same problem as phd member.i have read ur posts and thought may be u can help me too. my protein size is 22 kda and an impurity at 75 kDa. did the cut off membrane of 30kda worked in ur case?
I think the membrane is climbed on to a V formed apparatus and put on peak of a centrifuge tube . you burden your experiment to it and rotate at 4000 rpm at 4 C for 30 min to 2 hr. If your fragment does not pattern dimer or certain thing, you may trial the one with 30k MWCO.
shane on Jun 10 2010, 11:49 AM said:
tats a bit tricky in this case.. as the difference is just 8 kDa... the thumb rule is use at least double or half the cut off depending on were u want it... as retentate or permeate!!! why dont u try a GFC??!!! although i think the amicon is easier to do!!