Reagents for Electrophoresis

Electrophoresis is a technique which separates charged biomolecules based on the rate at which they migrate in an applied electrical field. In many cases, electrophoresis of proteins are performed using polyacrylamide gel electrophoresis (PAGE).1) For molecular weight estimation and purity determination of proteins, sodium dodecyl sulfate (SDS)-PAGE is frequently employed. SDS is a strong denaturant of proteins and is added to samples, gels, and buffer solutions for electrodes when proteins are separated with electrophoresis. As SDS not only denatures protein but also binds to the protein, when SDS is used in conjunction with a reducing reagent such as 2-mercaptoethanol to cleave disulfide bonds in the protein, and the protein is completely denatured, the amount of SDS bound is almost always proportional to the molecular weight of the protein. Resultantly, the protein is negatively charged. Therefore, the denatured protein can be separated by molecular weight independently of its structure and biological properties.