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SDS stands for Sodium Dodecyl Sulphate and has the chemical formula C12H25SO4Na [1]. 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 surfactant and, more precisely, as a detergent. SDS is found in common products such as shampoos [2]. SDS also plays an essential role in SDS-PAGE electrophoresis [3]. In this procedure, proteins are separated based on their net negative charge, molecular weight and shape. 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 [4]. The negative charge on SDS suppresses the native charge on the protein being analysed. In this way, all the proteins being analysed have approximately the same negative charge and will move across the gel pulled by the electrostatic attractions according to their size only.


  1. Sodium Dodecyl Sulfate. 2009. 27 November 2010.
  2. Caprette, David R. Experimental Bisociences. 11 Sep. 2001. 27 Nov. 2010
  3. Berg, Jeremy M., John L. Tymoczko, and Lubert Stryer. Biochemistry. New York: W. H. Freeman, 2007. Page 72
  4. Biochemistry. 28 Nov. 2003. University of Arizona. 27 Nov. 2010​classes/​bioc462/​462a/​notes/​protein_properties/​protein_purification.htm
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