SDS-PAGE problem

R. John Lye rjl6n at
Tue Nov 20 07:29:36 EST 2001

Jayakumar R wrote:

> The concentration of Bis in the gel is 1.6% (double the
> normal of 0.8%). The Bis concentration is high since I need to use the gel
> for seperating two proteins which differs by only 1 kDa.

This might be a problem.  Its been a while since I looked at the charts
of pore size vs bis concentration,but as I recall the pore size got larger
as you went away from 0.8% in either direction (lower or higher
concentration).  I would suggest going back to the standard recipe,
and as D.K. suggested, making sure that you're using the right acrylamide
concentration for the molecular weight range that you're trying to
separate.  Also, I've generally had better results using constant voltage
than when I used constant current,so you might try that.

Good luck,

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