Hello I am trying to complex two proteins of 57 and 18 kda and using pET 22b as an expression system. I purified both with His tag and the purity is quite nice after Ni-NTA (Buffer is Tris,Nacl and Imidazole). After purification with Ni_NTA i tried to improve my protein purity using gel filteration(superdex-200). I successfully got the 57 Kda with a high purity (Buffer is Tris and nacl) but with the smaller protein i didnt get anything after the column. when i tried dialysis to remove imidazole from this 18kda protein it degraded.i tried protease inhibitors as well but still the protein is not stabilised. Can anyone suggest me something to get out from this. I am stuck at this stage. suggestion are highly welcomed and appreciated.
-- INTEKHAB ALAM LABORATORY OF STRUCTURAL BIOINFORMATICS KOREA UNIVERSITY, SEOUL