title: Visual indicator for surfactant abundance in MS-based membrane and general proteomics applications.
abstract: The existence of surfactants in proteomics samples can severely reduce enzymatic digestion efficiency, liquid chromatography (LC) separation efficiency, column lifetime, and mass spectrometry (MS) sensitivity. Although various techniques are able to remove surfactants, surfactants may occasionally be retained in samples due to variations in sample preparation method or personal skill. Evaluation of surfactant residue in a sample, however, usually requires an additional instrument and is time-consuming. In this study, a simple and rapid visual indicator for surfactant abundance (VISA) was developed. With the detection of a visible surfactant pellet in the solution, this assay was able to detect surfactant residue in aqueous solutions within 5 min. Without the need of additional equipment such as a mass spectrometer, every user can perform a quick test on their bench before sending the sample to the MS facility. The detection limit for the commonly used surfactants, Triton X-114 and SDS, was about 0.0005% and 0.0002%, respectively. The VISA was successfully applied to evaluate the efficiency of removal of surfactants in Triton X-114 extracted membrane proteins using tube-gel. With the combination of Triton X-114 extraction and tube-gel protocol, a study of spermatozoa membrane proteome identified about 252 proteins of which about 67.5% were classified as membrane proteins. The coexistence of protein and surfactant did not affect the VISA sensitivity, suggesting that this indicator is suitable for proteomics applications. The VISA also has potential for the detection of other surfactants and can be applied to other surfactant removing protocols.
authors.affiliation: Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan 11529.
authors.forename: Chao-Jung
authors.initials: CJ
authors.lastname: Chen
authors.forename: Mei-Chun
authors.initials: MC
authors.lastname: Tseng
authors.forename: Han-Jia
authors.initials: HJ
authors.lastname: Lin
authors.forename: Ting-Wei
authors.initials: TW
authors.lastname: Lin
authors.forename: Yet-Ran
authors.initials: YR
authors.lastname: Chen
mesh_terms: D000818:Animals; D006801:Humans; D007202:Indicators and Reagents / Q000737:chemistry*; D019169:Jurkat Cells; D008297:Male; D008565:Membrane Proteins / Q000737:chemistry; D051379:Mice; D017830:Octoxynol; D011092:Polyethylene Glycols / Q000737:chemistry; D040901:Proteomics / Q000379:methods*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013094:Spermatozoa / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D007202:Indicators and Reagents; D008565:Membrane Proteins; D013501:Surface-Active Agents; D012967:Sodium Dodecyl Sulfate; D011092:Polyethylene Glycols; D017830:Octoxynol; C010615:Nonidet P-40