What are polyacrylamide gels?

Polyacrylamide gels are a matrix of cross-linked acrylamide monomers with the tightness of the mesh dependent upon the amount of acrylamide and cross-linker present. Different sized proteins therefore require different formulations of acrylamide gel to achieve optimum separation (table 1).

How are polyacrylamide gels prepared?

Polyacrylamide gels are prepared by polymerization of an acrylamide monomer and N,N'-methylene-bis-acrylamide cross-linker. The polymerization reaction can be initiated by chemical reaction in the presence of ammonium persulfate and N,N,N,N-tetramethylenethylenediamine (TEMED) or photochemical reaction by riboflavin in the presence of UV radiation.

Why do acrylamide gels migrate in SDS-PAGE?

In SDS-PAGE all proteins are denatured and have a uniform negative charge applied to them therefore migration is due to difference in size between proteins. Polyacrylamide gels are a matrix of cross-linked acrylamide monomers with the tightness of the mesh dependent upon the amount of acrylamide and cross-linker present.

Can acrylamide be used as a gel?

Gels can either use a single concentration of acrylamide where they are optimised for a narrow range of molecular weights (see section 1) or be gradients of acrylamide concentration where they are optimised for a much wider range of weights (see section 2).

Which pore size is needed for polyacrylamide gel?

Generally the larger the protein the larger pore size is needed in the polyacrylamide gel and the smaller the protein the smaller the pore size (table 1). Once the gel concentration needed has been identified these can either be purchased as pre-cast gels or made in the laboratory using the recipe in table 2. Table 2.

What is sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE)?

Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) is an essential molecular biology technique where complex mixtures of protein are separated in an acrylamide gel according to their molecular weight.