MOF-constrained Rh enables stable in situ H2O2 supply for peroxide-dependent enzymes

Peroxide-dependent enzymes often suffer from irreversible oxidative deactivation by the peroxide co-substrate. Transition metal mediated in situ generation of H 2 O 2 offers continuous peroxide feeding in low concentration. However, free metal complexes often interact non-selectively with proteins, leading to mutual deactivation of metal catalysts and enzymes. Here, we report a spatial isolation strategy using zirconium-based metal-organic frameworks (UiO-67) to immobilize the transition metal catalytic unit [Cp*Rh(bpy)Cl]⁺. The porous MOF structure acts as a molecular sieve, excluding enzymes from the Rh sites on the framework, thus protecting both catalysts from mutual deactivation. The Rh modified UiO-67 (Rh@UiO-67) catalyzes the flavin-mediated electron transfer from formate to oxygen, generating H 2 O 2 in a formate oxidase mimicking fashion. Its protein compatibility allows Rh@UiO-67 to fuel peroxyzymes for stable oxyfunctionalization. Compared to natural formate oxidase, this system also shows high stability to various pH and temperatures, enabling its application in versatile conditions.