PAGE gels- can you make up to 20% with Tris/Glycine?

[Keith Pitts]

We generally use a standard homemade 12% Tris/Glycine SDS-PAGE gel
procedure (from Current Protocols) for our proteins, but are trying to
get tighter separation.  I have seen recipes for up to 15% acrylamide
gels in the glycine system.  Does anyone know if you can go up to 20% or
so in this system?  What, if any consequences are there, and how does it
affect the separation of the proteins?  We are looking at a ~17kD
DNA-binding protein and would like to save tricine buffer recipes/gels
as a last resort as they would be significantly less convenient.

Thanks much
Keith

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Keith Pitts
Research Assistant            Univ. of Georgia
k20man at arches.uga.edu