Sample Preparation for Shotgun Proteomics by Using Phase Transfer Surfactants

Abstract

We have reported a phase transfer surfactants (PTSs)-aided sample preparation protocol for shotgun proteomics. The PTS protocol using deoxycholate and lauroylsarcosin increases the solubility of membrane proteins and enhances trypsin and lysyl endopeptidase activities. The PTSs become more hydrophobic at acidic pH. Based on this property, PTSs are removable from sample solutions by the liquid-liquid extraction method with ethyl acetate as organic solvent, while peptides are remained in the aqueous phase. Compared with protocols using a RapiGest or a filter–aided sample preparation protocol, the number of identified proteins and the recovery of peptides are significantly increased in the PTS protocol, suggesting that the PTSs protocol is more effective for the large-scale unbiased proteomics than these protocols.