Achieving efficient photo-enzyme coupling via a novel diketone derivative to expand the scope of enzyme action

• BDC-AA with novel diketone structure is proposed for photo-enzyme coupling. • A stable complex is formed via hydrophobic interactions with residues such as Phe265. • BDC-AA can boost laccase-mediated degradation of non-enzymatic substrate EDTA. • The system generates a long-lived intermediate (∼527 ns), indicating robust stability. • The substrate pocket bound to BDC-AA also affects the spatial structure of laccase. This study presents a novel visible light‑responsive diketone derivative, 3‑terphthalic acid azoacetylacetone (BDC‑AA), designed to extend fungal laccase (EC 1.10.3.2) catalytic activity. Experimental results show that BDC‑AA binds specifically to laccase's substrate binding pocket, enabling efficient electron transfer from the molecule's photoexcited state to the enzyme's T1Cu center. This interaction significantly promotes the oxidation of otherwise non‑native substrates, ethylenediaminetetraacetic acid (EDTA) under visible light irradiation. Molecular docking, fluorescence quenching, and circular dichroism analyses reveal the structural basis of the BDC‑AA–laccase complex, confirming the stability and enhanced electron transfer efficiency. The combined system operates without additional sacrificial agents or cofactors, highlighting a promising avenue for green biocatalysis and environmental remediation applications.