Vanadium-dependent haloperoxidases: Recent advances and perspectives

Vanadium-dependent haloperoxidases (VHPOs) represent a distinct class of halogenating enzymes that catalyze the oxidation of halide ions into hypohalous acids using hydrogen peroxide and a redox-stable vanadate cofactor. In recent years, VHPOs have gained considerable attention in synthetic community due to their exceptional operational robustness, broad substrate tolerance, and particularly, the potential in driving green halo-compound synthesis. The rapid progress using VHPOs in organic synthesis inspires this review covering VHPOs discovery, structure-function insights, mechanistic elucidation, and various synthetic applications. Special attention is given to recent breakthroughs in understanding the halide and substrate specificity of VHPOs, including the identification of substrate-access tunnels and enzyme-bound halogenation mechanisms. These findings not only challenge the long-standing diffusible HOX model but also enable rational enzyme engineering. VHPOs are emerging as powerful tools for selective halogenation and sustainable synthesis, with promising prospects in synthetic biology, materials science, and environmental biotechnology.