Use of Octylbenzenesulfonate in Place of Dodecyl Sulfate in SDS-Polyacrylamide Gel Electrophoresis

Sodium n-octylbenzene-p-sulfonate was successfully used in place of sodium dodecyl sulfate in SDS-polyacrylamide gel electrophoresis. This modification of the usual technique made it possible to scan the polyacrylamide gel for the distribution of the surfactant by measurement of UV absorption. It was found that a band electrophoresed in advance of the complexes formed between protein polypeptides and the surfactant. The band could be observed even in the absence of protein polypeptide, and was ascribed to micelles derived from surfactant added in excess to the sample solution. The complexes were found to be detectable by scanning at 261 nm, usually with better sensitivity than by scanning at 280 nm. Thus, this modification of SDS-polyacrylamide gel electrophoresis is useful both to investigate what is going on in the gel during electrophoresis and to improve the sensitivity of detection by UV scanning of protein complexes.