SDS is used in cleaning procedures, and is commonly used as a component for lysing cells during RNA extraction or DNA extraction, inhibiting the activity of nucleases, enzymes that can degrade DNA, protecting the integrity of the isolated genetic material, and for denaturing proteins in preparation for electrophoresis in the SDS-PAGE technique.
In the case of SDS-PAGE, the compound works by disrupting non-covalent bonds in the proteins, and so denaturing them, i.e. causing the protein molecules to lose their native conformations and shapes. By binding to proteins at a ratio of one SDS molecule per 2 amino acid residues, the negatively charged detergent provides all proteins with a similar net negative charge and therefore a similar charge-to-mass ratio. In this way, the difference in mobility of the polypeptide chains in the gel can be attributed solely to their length as opposed to both their native charge and shape. This separation based on the size of the polypeptide chain simplifies the analysis of protein molecules.