rule of thumb for SDS-PAGE separation of small proteins?
blaesse at biochem.mpg.de
Wed Oct 28 05:37:41 EST 1998
On Tue, 27 Oct 1998, scorbitt wrote:
> If you would like to increase your separation, I would reduce the percentage
> of acrylamide/bis in your gels. Try a 10% or 12%.
This would be right, if the proteins are about 90 kDa (800 amino acids)
or more. For the small proteins this doesn't help at all. I would try a
20% gel (no gradient). A gradient gel is usefull if you want to separate
small and large proteins on the same gel.
> > I have to separate two proteins with 105 and 107 amino acids. We
> > usually use a 16% Tricine SDS-PAGE. But I sometimes don't get a
> > consistent separation. I wonder if there is a rule of thumb for a small
> > protein separation? Would a 20% gel be better? Or maybe a 10% - 20%
> > gradient gel? Ideally, the two bands should be at least 1 mm apart
> > after staining.
> > Ing-Nang Wang
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