When we develop our gel we recently keep getting a horizontal line of stain at 50000 mol weight in all lanes of our gel. (This is not a feature of interest except that the protein that we are interested happens to be 50000 mol weight). I would appreciate any ideas on how we can get rid of this line.
Are these somewhat fuzzy bands? If yes then it's [human] keratins. Usually it is either SDS or bME stocks that get contaminated with keratins. Usually, just changing stocks and working cleanly solves the issue but occasionally bME as bought already contains them.
Ochs, D. (1983) Protein contaminants of sodium dodecyl sulfatepolyacrylamide gels. Anal. Biochem. 135, 470–474. Dima
