Photocatalytic Regeneration of Nicotinamide Cofactors by Quantum Dot-Enzyme Biohybrid Complexes

We report the characterization of biohybrid complexes of CdSe quantum dots and ferredoxin NADP(-)(+)reductase for photocatalytic regeneration of NADPH. Illumination with visible light led to reduction of NADP+ to NADPH, with an apparent k(cat) of 1400 h(-1). Regeneration of NADPH was coupled to reduction of aldehydes to alcohols catalyzed by a NADPH-dependent alcohol dehydrogenase, Aldehyde with each NADPH molecule recycled an average of 7.5 times. The quantum yield both of NADPH and alcohol production were 5-6% for both products. Light-driven NADPH regeneration was also demonstrated in a multienzyme system, showing the capacity of QD-FNR complexes to drive continuous NADPH-dependent transformations.