Development of Fluorogenic Reagent that Enables Simultaneous Detection and Labeling of Hydropersulfide

Real-time detection and identification of modified cysteine sulfhydryl (Cys-SH) residues are important because supersulfidation (S-sulfhydrylation) alters protein function and thereby modulates the activity of biological systems. Although fluorescence probes for rapid, sensitive detection and biotin tag-switch methods for comprehensive labeling of modified residues at the proteome level have been developed, simultaneous detection and labeling have not been achieved in a single system. Herein, we describe dinitrobenzene-based fluorogenic probes with tunable electrophilicity, which react rapidly and selectively with highly nucleophilic supersulfides such as cysteine persulfide (Cys-SSH) and Na₂S₂ and simultaneously label Cys-SSH itself with a dinitrobenzene tag.