Visual Indicator for Surfactant Abundance in MS-Based Membrane and General Proteomics Applications

摘要

The existence of surfactants in proteomics samples cannseverely reduce enzymatic digestion efficiency, liquidnchromatography (LC) separation efficiency, column lifetime,nand mass spectrometry (MS) sensitivity. Althoughnvarious techniques are able to remove surfactants, surfactantsnmay occasionally be retained in samples due tonvariations in sample preparation method or personal skill.nEvaluation of surfactant residue in a sample, however,nusually requires an additional instrument and is timeconsuming.nIn this study, a simple and rapid visualnindicator for surfactant abundance (VISA) was developed.nWith the detection of a visible surfactant pellet in thensolution, this assay was able to detect surfactant residuenin aqueous solutions within 5 min. Without the need ofnadditional equipment such as a mass spectrometer, everynuser can perform a quick test on their bench beforensending the sample to the MS facility. The detection limitnfor the commonly used surfactants, Triton X-114 andnSDS, was about 0.0005% and 0.0002%, respectively. ThenVISA was successfully applied to evaluate the efficiencynof removal of surfactants in Triton X-114 extractednmembrane proteins using tube-gel. With the combinationnof Triton X-114 extraction and tube-gel protocol, a studynof spermatozoa membrane proteome identified about 252nproteins of which about 67.5% were classified as membranenproteins. The coexistence of protein and surfactantndid not affect the VISA sensitivity, suggesting that thisnindicator is suitable for proteomics applications. The VISAnalso has potential for the detection of other surfactantsnand can be applied to other surfactant removing protocols.