SDS PAGE

Principle of SDS-PAGE

The principle of SDS-PAGE states that a charged molecule migrates to the electrode with the opposite sign when placed in an electric field. The separation of the charged molecules depends upon the relative mobility of charged species.

The smaller molecules migrate faster due to less resistance during electrophoresis. The structure and the charge of the proteins also influence the rate of migration. Sodium dodecylsulphate and polyacrylamide eliminate the influence of structure and charge of the protein , and the proteins are separated based on the length of the polypeptide chain.

Role of SDS in SDS-PAGE

SDS is a detergent present in the SDS-PAGE sample buffer. SDS along with some reducing agents function to break the disulphide bonds of proteins disrupting the tertiary structure of proteins.