he first step in Western blotting is sodium dodecyl sulphate- polyacrylamide gel electrophoresis (SDS-PAGE), followed by protein transfer on a membrane and subsequent detection with specific antibodies. Because the SDS-PAGE is conducted in denaturing conditions, proteins migrate according to their molecular weight, irrespective of secondary/tertiary structure, charge or protein-protein interactions. Consequently, the size of the protein can be determined as smaller proteins migrate faster than their larger counterparts.
