Gel Dialysis Of Protein Samples

Dialysis Molecular Weight And Size

This protocol describes a simple method for dialyzing small interfering molecules and salts away from protein samples using an agarose or polyacrylamide gel (see Fig. 3.4.5 Freifelder and Better, 1982). Somewhat dense, well cross-linked gels are used to keep proteins from penetrating the gel while unwanted salts and low-molecular-weight compounds diffuse (are dialyzed away) into the gel. This is a micro to semimicro method, an alternative to conventional dialysis (Craig, 1967), and to the use...

Peptide Sample Preparation by Ether Precipitation

This procedure is suitable for precipitating peptides from organic acids and is used routinely for concentrating synthetic peptides from the trifluoroacetic acid cleavage cocktail following 9-fluorenylmethyloxycarbonyl Fmoc solid-phase peptide synthesis. It can be used to desalt peptides in nonvolatile buffers but is not recommended for removing detergents like SDS. Take appropriate safety precautions when using this technique ether is highly flammable, and a refrigerated centrifuge and fume...