Dear All
I am working on AlkB family proteins, Here I am facing a problem in protein purification step. I am using His-tagged protein and trapped and purified by Ni-resin column. I could purified the protein and it was shown from SDS-PAGE analysis, but problem is, it is precipitating after elution from column using 100 mM Imidazole-25mM K2HPO4 as a eluting buffer and it does not precipitating when I used pure 100mM Imd solution (bellow pH 7 and it is not suggested for protein activity assay studies.
can any one suggest me, what is the problem i am facing and how it can be solved, what are suitable condition and buffer should I use ?