SDS polyacrylamide-gel electrophoresis
SDS-polyacrylamide-gel electrophoresis is a technique used to seperate proteins by their net negative charge, molecular weight and size. This is achieved through creating a gel containing cross-links of acrylamide subunits (polyacrylamide), which produces a matrix in which proteins can migrate towrds the positive end when a electrical current is applied [1]. Proteins which are smaller in size migrate through the gel faster and therefore travel further on the gel than those which are larger in size. This method can also be used for membrane proteins which are typically insoluble in water due to the seperation occuring as a result of the size of the polypeptide chain. Dyes such as Coomassie Blue are used to stain and identify major proteins whereas silver or gold stain is used to highlight smaller proteins[2].