Selenenylsulfide covalent-directed chemistry for the detection of sulfhydryl groups using a diselenide fluorescent probe

We report the development of a diglycosyldiselenide-based fluorescent probe for the rapid detection of sulfhydryl-containing biomolecules. The probe facilitates a chemoselective coupling reaction with sulfhydryl groups in aqueous buffer under ambient conditions, resulting in the formation of homogeneous Se-S conjugates within one hour. Using glutathione, a sulfhydryl-containing biomolecule, as a proof of concept, the probe achieved a detection limit of 0.75 μM based on the 3σ criterion. The method was further extended to the fluorescent labeling of cysteine-containing peptides, proteins, and living bacterial cells, showcasing the utility of Se-S covalent-directed chemistry as an analytical tool. This approach underscores the considerable potential of diglycosyldiselenide-based fluorescent probes for broader applications in biochemical research.