SP3-FAIMS Chemoproteomics for High Coverage Profiling of the Human Cysteinome

We report a new cysteine chemoproteomic method, termed SP3-FAIMS chemoproteomics, which enables rapid and high coverage analysis of the human cysteinome. By combining enhanced cysteine biotinylation with SP3 sample decontamination and FAIMS online fraction, we identified in aggregate 34,225 unique cysteines found on 7,243 proteins. Showcasing the versatility of our method, integration with the isoTOP-ABPP workflow enabled the high throughput discovery of cysteines labelled by electrophilic compounds.