A Protocol for Top-Down Proteomics Using HPLC and ETD/PTR-MS

Analysis of intact proteins by tandem mass spectrometry has mostly been confined to high-end mass spectrometry platforms. This protocol describes the application of routine HPLC to separate proteins, MALDI-ToF mass spectrometry to interrogate intact protein species and electron transfer dissociation/proton transfer reaction within a quadrupole ion trap to perform tandem mass spectrometry.