"mystery bands" in SDS-PAGE
Stephen R. Decker
Sdecker at Vines.colostate.edu
Thu Mar 28 23:15:21 EST 1996
I have seen this fairly frequently, most notably when silver staining. The
usual causes are:
1. Using glass bottles to store buffers and reagents. Protein sticks to glass
and slowly goes into these solutions. Old serum bottles are notorious for
this. If you must use glass, clean extremely well and soak in dilute NaOH,
then rinse well.
2. Not wearing gloves when handling the system.
Try loading a lane with just loading buffer and run the gel. It will tell you
if the problem is in the Laemmli. Also, if you use a stacking gel, run one
without it. Problem could be in stacking gel buffer. It probably is not in
the resolving gel buffer, since the proteins would be uniformly spread
throughout it, ditto for tank buffer.
Good Luck, let us know how it turns out.
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