I would strongly recommend that you use a continuous %T gel for the reason that
you mentioned: pore size. I had much better result in doing in-gel digest with
such a system than with a gradient gel. Use a 12 %T gel with a 2x Laemmli buffer
running at 16 mA constant per gel (mini-gel system, 1 mm thickness), the run
will last approx. 2-2.5 h (the key, here, is to run the gel slowly.) With a
minigel, you should get separation down to 6 kDa (running front of Bromophenol
Blue).
Good luck
Axel
-- Axel Ducret, Ph.D. Senior Research Biologist Merck-Frosst Canada Inc. Dept. Biochemistry and Molecular Biology P.O. Box 1005 Pointe-Claire-Dorval PQ H9R 4P8 Canadatel. + (514) 428-3428 fax + (514) 428-4900