Denaturing chemicals can be added to the acrylamides during the formation of polyacrylamide gels. These additives keep the solutes or molecules in a denatured state during separation. Urea denatures double-stranded DNA to single-stranded DNA. A detergent, sodium dodecyl sulfate (SDS), denatures proteins. Adding SDS with heat denatures proteins to small, similar-shaped particles and coats each so protein structures are not reformed. SDS is usually added to the gel and the protein sample. The mixture of protein-coated fragments then moves through polyacrylamide gel pores at speeds similar to a mixture of DNA fragments.
