"mystery bands" in SDS-PAGE

Stephen R. Decker Sdecker at Vines.colostate.edu
Thu Mar 28 23:15:21 EST 1996


Fiona,

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.

Steve Decker




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