Generating cysteine-trypsin cleavage sites with 2-chloroacetamidine capping.

An electrophilic arginine mimetic, 2-chloroacetamidine (CAM), was deployed to enable trypsin-mediated proteolysis at cysteine residues and to enhance mass spectrometry-based proteomic detection of cysteine-containing peptides. Illustrating the value of the CAM-capping strategy, proteogenomic analysis using a two-stage false discovery rate (FDR) search revealed 450% enhanced coverage of missense variants, when compared to established workflows. [ABSTRACT FROM AUTHOR]