The interaction of dodecyl and tetradecyl sulfate with proteins during polyacrylamide gel electrophoresis.

1. The affinity of tetradecyl sulfate for many unfolded proteins is greater than that of dodecyl sulfate. 2. It is the presence of tetradecyl sulfate that results in the staining of proteins by pinacryptol yellow seen by Stoklosa and Latz (Stoklosa, J.T. and Latz, H.W. (1974) Biochem. Biophys. Res. Commun. 58, 74--79), as some tetradecyl sulfate remains associated with proteins during electrophoresis at room temperature (as opposed to dodecyl sulfate which, within the limit of detection, is completely removed). 3. Tetradecyl sulfate has a greater capacity to dissociate protein aggregates which consist of identical peptide chains, such as Glycophorin dimers and bovine serum albumin dimers, than does dodecyl sulfate.