Appendix a: theory and recipes – Hoefer SE900 User Manual
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Appendix A: Theory and Recipes
Laemmli System Gels
The Laemmli system is the most common electrophoresis protocol for
SDS-denatured proteins.
The leading ion in this discontinuous buffer system is chloride and the
trailing ion is glycine.
Accordingly, the resolving gel (and the optional stacking gel) contain
Tris-Cl buffers (of different concentration and pH), and the electro-
phoresis buffer contains Tris-glycine. All buffers contain 0.1% SDS.
Polyacrylamide gel composition is indicated by two
different percentages:
% T = total acrylamide = [g (acryl + bis)]
× 100
100
% C = crosslinker =
g (bis)
× 100
g (acryl + bis)
The total percent of acrylamide (% T) in the resolving gel, which
can range from 5 to 20%, determines the pore size. Commonly, the
amount of crosslinker used (% C) is 2.6%.