What is the role of TEMED in activating ammonium persulfate in polyacrylamide gel polymerization?

The Role of TEMED in Polyacrylamide Gel Polymerization

TEMED (N,N,N',N'-tetramethylethylenediamine) plays a crucial role in the activation of ammonium persulfate (APS) in the process of polyacrylamide gel polymerization. Through this activation, the gel matrix necessary for molecular separation in techniques such as electrophoresis is formed.

During the preparation of a polyacrylamide gel for electrophoresis, APS is typically mixed with the acrylamide and methylenebisacrylamide solution along with TEMED. This mixture leads to the activation of APS by TEMED, triggering a series of chemical reactions that result in the formation of the gel matrix.

When TEMED comes into contact with APS, it acts as a catalyst by accelerating the formation of free radicals from APS. These free radicals then initiate the polymerization process of acrylamide and methylenebisacrylamide. As a result, a polyacrylamide gel matrix is formed, characterized by a network of pores that will later trap and separate molecules.

As the polymerization reaction progresses, the liquid acrylamide and methylenebisacrylamide solution solidifies, ultimately leading to the formation of a gel matrix with defined pore sizes determined by the ratio of acrylamide to methylenebisacrylamide crosslinking.