SDS

SDS stands for Sodium Dodecyl Sulphate and has the chemical formula C₁₂H₂₅SO₄Na . The hydrocarbon chain and the sulphate group are responsible for the amphiphilic properties of the molecule. These properties are essential for the role of SDS as a detergent. SDS is found in common products such as shampoos . SDS also plays an essential role in SDS-PAGE electrophoresis . In this procedure, where proteins are separated based on their size only, SDS binds to the proteins being analysed (in a ratio of approximately one SDS molecule per two amino acid residues) and breaks the noncovalent interactions in the protein . The negative charge on SDS suppresses the native charge on the protein being analysed. In this way, all the proteins that are being analysed have approximately the same negative charge and will move across the gel pulled by the electrostatic attractions according to their size only.