Unraveling and Manipulating of NADH Oxidation by Photogenerated Holes

Photoenzymatic coupled catalysis, integrating semiconductor photocatalysis and enzymatic catalysis, exhibits great potential for light-driven synthesis. To make a photocatalyst and an enzyme act concertedly, nicotinamide-based cofactors have been widely used as an electron carrier. However, these cofactors are easily oxidized into an enzymatically inactive form by photogenerated holes. Herein, the oxidation mechanism of NADH, one typical nicotinamide-based cofactor, by photogenerated holes was reported. With CdS, g-C3N4 , and BiVO4 as hole generators, NADH is oxidized into NAD+ or fragmented into ADP-ribose derivatives through a multistep electron transfer. Importantly, the fragmentation reaction is inhibited with dopamine and neutral red to coordinate electron transfer between NADH and photogenerated holes.