Coupling Sodium Dodecyl Sulfate−Capillary Polyacrylamide Gel Electrophoresis with Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry via a Poly(tetrafluoroethylene) Membrane

摘要

ABSTRACT: Sodiumdodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) is a fundamental analytical technique fornproteomic research, and SDS-capillary gel electrophoresis (CGE) is its miniaturized version. Compared to conventional slab-gelnelectrophoresis, SDS-CGE has many advantages such as increased separation efficiency, reduced separation time, and automatednoperation. SDS-CGE is not widely accepted in proteomic research primarily due to the difficulties in identifying the well-resolvednproteins. MALDI-TOF-MS is an outstanding platform for protein identifications. Coupling the two would solve the problem but isnextremely challenging because the MS detector has no access to the SDS-CGE-resolved proteins and the SDS interferes with MSndetection. In this work we introduce an approach to address these issues. We discover that poly(tetrafluoroethylene) (PTFE)nmembranes are excellent materials for collecting SDS-CGE-separated proteins. We demonstrate that we can wash off the SDSnbound to the collected proteins and identify these proteins on-membrane with MALDI-TOF-MS. We also show that we cannimmunoblot and Coomassie-stain the proteins collected on these membranes.