The best % acrylamide concentration for small proteins and peptides (<20 kDa): 16% Tris Tricine Gels.
Resolution of cyanogen bromide fragments of myoglobin by Tricine–SDS-PAGE (a) and Tris Glycine SDS-PAGE (b) using 10% T, 3% C gels. Hermann Schägger Nature Protocols 1, 16 – 22 (2006)
Tricine SDS-PAGE vs Tris Glycine SDS-PAGE. Which one is better for small peptides?
Uniform high-acrylamide Laemmli gels cannot be used to access the small protein range, because the stacking limit in the Laemmli system is too high, and small proteins usually appear as smearing bands near the gel front. In a less convenient way, however, the small protein and peptide range can be accessed by making use of gradient gels that continuously destack proteins according to decreasing mass during electrophoresis. Tris Tricine (a modification of the Laemmli system) gels—for example, 8–16% and 10–27% acrylamide gels for the ranges 6–250 kDa and 2–200 kDa, respectively—cover wide ranges of mass best.