Electrokinetic Removal of Sodium Dodecyl Sulfate from Proteins for Mass Spectrometry Analysis
Abstract
Transmembrane electrophoresis (TME) is an electrokinetic method designed to remove sodium dodecyl sulfate (SDS) from protein samples prior to mass spectrometry analysis. Proteins in solution are stored behind dialysis membranes while the electromotive force of an applied electric field drives the charged surfactant off the proteins and across the membrane. For optimal MS analysis, SDS must be depleted below 10 ppm. An actively cooled TME (AC-TME) system is presented that employs water-circulating tubes to mitigate Joule heat build up and to maximize the rate of SDS depletion. To further remove the potential for protein loss through TME purification, an in-situ TME trypsin digestion protocol was also developed and demonstrated here. The improved protein purification device and protocol presented removes one of the major bottlenecks in proteome analysis, enabling the use of SDS-based workflows in a robust and high throughput format, for proteomic LC-MS analysis.