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Purification of His tagged protein - (Feb/15/2011 )


I am purify a his tagged protein expressed in E coli Bl 21DE3. But after gel filtration there are still contamination of different size of protein. I tried Ion exchange chromatography but it did not worked. Is there any thing i can do so that the unexpected protein will not be expressed or how to purify that one



Usually His-tagged proteins are purified using a Ni-affinity column. You can play around with different concentrations of imidazole to try to achieve best purity.


try a different system like from HEK cells. sometimes, its difficult to get a pure protein prep from E.Coli.
but is the contamination a real problem for your exp.?