Highly Selective Fluorescent Probe Based on Hydroxylation of Phenylboronic Acid Pinacol Ester for Detection of Tyrosinase in Cells

The detection of tyrosinase, a biomarker for melanoma, is of great significance. Herein, a fluorescent tyrosinase probe, with resorufin as the fluorophore and m-tolylboronic acid pinacol ester as the receptor, is proposed. The response relies on the tyrosinase-catalyzed hydroxylation of phenylboronic acid pinacol ester at an adjacent position followed by 1,6-rearrangement elimination to release resorufin. This probe well quantifies tyrosinase in the range from 1 to 100 U mL–1 with a detection limit of 0.5 U mL–1. Importantly, the probe exhibits high selectivity for tyrosinase over other biological substances including reactive oxygen species. In addition, it is successfully applied to the imaging of tyrosinase in cells. This probe provides a novel platform for selective detection of tyrosinase in biosystems.