Tyrosinase Oxidative Cross-Linking in the Cell-Like Crowded Microenvironment for Visible Inhibitor Screening

Owing to many diseases and disorders being caused by dysfunctional or over/underexpressed enzymes, screening for inhibitors of pharmacologically relevant enzymes has emerged as a promising tool for drug discovery, clinical diagnostics, enzyme engineering, and other medical fields. However, despite the recent advances, most inhibitor screenings are still usually conducted in dilute media, at concentrations far from the media in which the enzymes are actually found, which may cause drugs to fail when translated to <i>in vivo</i>. Herein, we build a gel-like intracellular biological environment <i>in vitro</i> using a tyrosinase oxidative cross-linking hydrogel system that is closer to the real catalytic environment of enzymes. We report a straightforward and effective inhibitor evaluation strategy that can quickly compare the inhibitory strengths of inhibitors based on the principle that adding inhibitors causes color changes and mechanical changes in the system. Enabled by molecular docking, we further demonstrate the different performances of the inhibitors at different concentrations. By construction of the cell-like crowded environment <i>in vitro</i>, this system shows an appealing application prospect for new drug development.