Detection of Enzymatically Generated Hydrogen Peroxide by Metal-Based Fluorescent Probe

We developed a metal-based fluorescent probe for H2O2 called MBFh1, which has an iron complex as a reaction site for H2O2 and a 3,7-dihydroxyphenoxazine derivative as the fluorescent reporter unit. The iron complex reacts quickly with H2O2 to form oxidants, and then the oxidants convert the closely appended nonfluorescent 3,7-dihydroxyphenoxazine moiety to resorufin in an intramolecular fashion. The quick response to H2O2 allows us to plot the enzymatic evolution of H2O2. A combination of N-acetyl-3,7-dihydroxyphenoxazine and horseradish peroxidase has been frequently used to detect enzymatically generated H2O2, but this method has interference with phenol derivatives. The use of MBFh1 overcomes this drawback.