REGENERATION OF NAD⁺ AND NADP⁺ COFACTORS BY PHOTOSENSITIZED ELECTRON TRANSFER

Abstract

Abstract The irradiation with visible light of photosensitizer dyes like methylene blue or N‐methyl phenazonium methyl sulfate leads to the oxidation of reduced coenzymes such as pyridine nucleotides (NADH or NADPH). This photoredox reaction can be used to regenerate the oxidized form of these coenzymes in enzymatic reactions and total consumption of a substrate with catalytic amounts of enzyme, coenzyme and photosensitizer can be performed. The process has been studied on two common enzymatic reactions: ethanol oxidation by alcohol‐NAD + ‐oxidoreductase and gluconate‐6‐phosphate oxidation by 6‐phospho‐D‐gluconate‐NADP + ‐2‐oxidoreductase. In the first case, a turnover number of 1125 has been obtained for the photoregeneration of NAD + from NADH.