Catalytic peptide-driven reaction of cyano-containing fluorescent dye with H2O2: A fast and highly sensitive tool for fluorescent detection of hydrogen peroxide in living cells and aqueous solutions

초록

Protein-based fluorescent probes that utilize Cys residue oxidation by H2O2 have demonstrated excellent performance in detecting H2O2 in live cells compared to small-molecule probes. However, the precise roles of amino acid residues in recognizing and interacting with H2O2 in these proteins are not yet fully understood. To address this limitation, we pioneered the use of catalytic peptides to facilitate a highly selective reaction between the nitrile group of a visible-light-excited fluorophore and H2O2. This innovation resulted in the development of a first-in-class fluorescent probe, combining catalytic peptides with a nitrile-substituted fluorophore. The probe exhibits exceptional performance, including ratiometric detection, a rapid response rate (kobs = 8.3 x 10-3 s-1), high sensitivity (LOD = 640 nM), and outstanding selectivity for H2O2 under physiological conditions in both aqueous solutions and live cells. Notably, the probe's reaction rate constant is comparable to those of the fastest H2O2 fluorescent sensors reported to date. This study underscores the novel capability of catalytic peptides to convert the nitrile group of a fluorophore into an amide group via H2O2, offering significant advancements in fluorescent sensing of H2O2 and potential applications in green chemistry for sustainable amide synthesis.

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