A technique to dissociate multimeric proteins and to separate all proteins according to their apparent molecular masses. Proteins are treated with sodium dodecyl sulphate (SDS), an anionic detergent, and separated by electrophoresis on polyacrylamide gels that incorporate SDS. The detergent adsorbs on to the proteins in proportion to their mass and dominates their electric charges. Also known as denaturing gel electrophoresis or SDS gel electrophoresis.