Facile Fluorescence-Based Detection of PAD4-Mediated Citrullination

PAD off, fluorescence on: Protein arginine deiminase 4 (PAD4), an enzyme that has been found to be overexpressed in numerous human cancers and autoimmune diseases, converts peptidyl-arginine to citrulline. We report a new fluorescence-based assay for the detection of PAD4 activity that exploits the substrate specificity of trypsin.