Abstract
Protein S-sulfenylation(protein sulfenic acid),as one of the most significant oxidative post-translational modifications(OxiPTMs),plays a vital role in regulating protein function.A variety of activity-based probes have been developed to profile sulfenic acid in living cells.However,due to the transient pres-ence and low content of sulfenic acid in living cell,high doses of probes are needed to achieve efficient labeling.More importantly,current probes have no temporal control over sulfenic acid labeling.To over-come these limitations,two caged cysteine sulfenic acid probes DYn-2-ONB and DYn-2-Cou with either an o-nitrobenzyl or coumarin protecting group were developed in this study.Both probes can be effi-ciently uncaged via irradiation to produce the active C-nucleophile probe DYn-2.Labeling assay in living cells demonstrated DYn-2-ONB exhibited better labeling capacity compared with DYn-2,providing it as a powerful tool for improved monitoring of protein S-sulfenylation in living cells.