Enzyme-driven oxygen-fuelled pathway selectivity of tyrosine-containing peptide oxidation evolution

The pathway selectivity of chemical evolution controlled by enzymes, with proteins and peptides as substrates, is of critical significance to determine biological processes and functions. In nature, organisms utilize tyrosinase to catalyse oxidation reactions of tyrosine to produce multifunctional compounds in different pathways. However, it remains a great challenge to manipulate the pathway selection of tyrosinase-guided chemical evolution for achieving biomaterials with on-demand functions. We herein report that controlling oxygen concentration is effective in regulating the evolution of tyrosinase-catalysed oxygenation pathways of tyrosine-containing peptides and even proteins. The melanin formation pathway predominates under oxygen-enriched conditions, while fluorescent compounds are preferentially generated under hypoxic conditions. The chemical evolution of tyrosine-containing peptides, regardless of their neighbouring amino acid types and sequences, tends to be governed by these two competitive pathways. These competitive pathways are manipulated by conformational transformation of tyrosinase active centre that is determined by oxygen concentration. Moreover, the oxygen-controlled chemical evolution of tyrosine-containing biomolecules can be broadly realized by tyrosinase to obtain melanin-based photothermal materials or multicolour fluorescent materials. This work reveals the plausible role of oxygen in the pathway selectivity of enzyme-controlled chemical evolution of tyrosine-containing peptides and verifies the possibility of fluorescent detection in living cultured melanoma cells, which provides a versatile strategy for precise design and engineering of tyrosine-involved multifunctional biomaterials