I have problems running SDS-PAGE gels because a pencil-like line runs
continuously from one end of the gel to the other end of the gel
horizontally at about 3/4 of the way down on the gel when I do the
silver staining. I am not sure why that happens and do not know how
to get rid of it. The strange thing is when I use commassie blue to
stain a different gel (not the same gel as silver but contain the same
samples), a color gradient appear across the gel. The top appear
almost colorless. The middle of the gel appears a light blue. The
bottom part of the gel (3/4 way down) appears a deeper blue than the
middle. I could not get the entire gel to stain a uniform blue color.
Could the problems with these two gels be the running buffer
contaminants or is it something else? I washed the SDS off the gel
very well so I believe that is not the problem. Please help! Thank
you.
