Question

Explain how treatment of proteins with sodium dodecyl sulphate (SDS) enables their separation by gel electrophoresis.

Answer 1

Sodium dodecyl sulphate (SDS) is used to eliminate the influence of charge and structure, and the proteins are separated only on the basis of polyeptide chain length through electrophoresis. SDS denatures and binds to proteins, making them uniformly negatively charged. As a result, on applying a current, all SDS bound proteins will migrate through the gel towards the positively charged electrode.

Thus, proteins of smaller size migrate faster, whereas, proteins of larger size migrate slower.