Problem in concentrating protein - (Jun/18/2008 )
My protein is 23kDA in size. After purifying it in the Ni-NTA column, I dialysed it against PBS and proceeded to concentrate it in the Milipore concentratore tube with 10000 MWCO.
On the SDS-gel, the non-specific bands above and below my protein weight was concentrated (I ran pre and post concentration samples), but there was no difference in the intensity of my protein band. This seemed strange to me.
What ur telling is very strange, but its happen to u probably because of very low concentration of ur
protein, so u cant relay compare the before and after fraction (start with larger volume of culture).
i think u should first concentrate the protein and then dialyzed. every method decrease the concentration
of the protein.