For the Impatient SDS Electrophoresis Without Stacker

As you are able to infer from the previous section, the Lammli system is a mature method that nevertheless has its weaknesses. Thus, time and again there are researchers who attempt to improve it, presumably with Lammli s citation cormt in mind. Ahn et al. (2001) claim to be able to do without the stacker by simply switching the buffer system. The resolution supposedly remains identical or is even a little better than with Lammli because the separation gel can be made longer. Above all, however, less (making of) solution is required. 

For the Ahn gel, you need acrylamide stock solution, running buffer, test buffer, and separation gel buffer. Acrylamide stock solution, running buffer, and test buffer are identical to the Lammli system. The secret lies in the separation gel buffer. In Ahn et al. it consists of 76 mM Tris-HCl and 0.1 M serine, 0.1 M glycine, and 0.1 M asparagine, with a pH of 7.4. Thus, the separation gel buffer does not contain any SDS. 

Separation gel without SDS for the SDS electrophoresis No problem The SDS from test buffer and running buffer rrms faster than the proteins (i.e., they remain in an environment that contains SDS). The advantage of the SDS-free separation gel with SDS-free test buffer and running buffer, the Ahn system becomes a native gel electrophoresis. 

This and the labor savings due to the missing stacker do not yet exhaust the advantages of the Ahn gel. Because the pH of the gel is only at 7.4, the gel can be stored at 4° C for about half a year without being damaged. In contrast, the acrylamide slowly hydrolyzes at the 8.8 pH of the Lammli system. 

Ahn et al. assure that in spite of the missing stacker the electrophoresis in the Ahn gel is insensitive to sample volume, to NaCl concentrations up to 0.5 M, and to 2% CHAPS or TRITON. The proteins also allow blotting. 

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