http://en.wikipedia.org/wiki/Sodium_dodecyl_sulfate Sodium lauryl sulfate From Wikipedia, the free encyclopedia (Redirected from Sodium dodecyl sulfate) ---------- SDS-PAGE Main article: SDS-PAGE Sodium lauryl sulfate, in science referred to as sodium dodecyl sulfate (SDS), is commonly used in preparing proteins for electrophoresis in the SDS-PAGE technique.[2] This compound works by disrupting non-covalent bonds in the proteins, denaturing them, and causing the molecules to lose their native shape (conformation). Also, anions of SDS bind to the main peptide chain at a ratio of one SDS anion for every two amino acid residues.[citation needed] This effectively imparts a negative charge on the protein that is proportional to the mass of that protein (about 1.4 g SDS/g protein). This new negative charge is significantly greater than the original charge of that protein. The electrostatic repulsion that is created by binding of SDS causes proteins to unfold into a rod-like shape thereby eliminating differences in shape as a factor for separation in the gel. Sodium lauryl sulfate is probably the most researched anionic surfactant compound. Like all detergent surfactants (including soaps), sodium lauryl sulfate removes oils from the skin, and can cause skin and eye irritation. The critical micelle concentration (CMC) in pure water at 25°C is 0.0082 M[3], and the aggregation number at this concentration is usually considered to be about 62[4]. The micelle ionization fraction (α) is around 0.3 (or 30%).[5] ---------- 3. ^ P. Mukerjee and K. J. Mysels, "Critical Micelle Concentration of Aqueous Surfactant Systems", NSRDS-NBS 36, US. Government Printing Office, Washington,.D.C., 197 1. --

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