Specific Imaging of Tyrosinase in Vivo with 3-Hydroxybenzyl Caged D-Luciferins

Tyrosinase (TYR), a key enzyme in biosynthesis of melanin, usually functions as a biomarker of severe skin diseases such as vitiligo and melanoma cancer. Accurate detection of TYR activity in vivo is urgent but still challenging. Inspired by the advantages of bioluminescence in vivo strategy in imaging and the specific hydroxylation of 3-hydroxybenzyloxy group by TYR, a bioluminogenic probe, TYR-LH₂, was designed and synthesized through caging D-luciferin with 3-hydroxybenzyl. The probe exhibits high selectivity and sensitivity toward TYR with a detection limit of 0.11 U/mL in a small detection volume of 100 μL. Bioluminescence imaging results show that TYR-LH₂ is fully competent for monitoring the dynamic changes of TYR in living cells and model animals and possesses the capability of discriminating melanocytes from other cell lines, thus offering a promising approach for investigation and diagnosis of melanoma cancer and other TYR-related diseases in vivo.