Highly selective detection of disulfenylated proteins through a dimedone-based fluorescent probe and application in cells

A novel fluorescent probe, 2, 4-cyclohexanedione-1-propyl-pyrene (TAR), has been synthesized to research thioredoxin (Trx) disulfenylation and visualize the activity of Trx in cells. The turn-on fluorescence change was induced by combining the vicinal dithiol proteins with the spatially sensitive fluorescent signal of the pyrene excimer which emitted at 480 nm. Trx activity can be detected at nanomolar concentrations. Trx preference of TAR in vitro and in vivo was proved by fluorometric and confocal microscopic experiments. In addition, it could realize dynamic tracking of protein disulfenylation in situ with minimal disturbance to disulfenylated proteins and less perturbation with cellular function. We herein report the first turn-on fluorescent sensor for the selective detection of proximally disulfenylated protein sites, suitable for application in both aqueous solutions and in cells.