The photogeneration of nicotinamide adenine dinucleotide hydrophosphate (NADPH) and its associated reaction were studied in a novel photo-energy conversion system. The system was composed of the oligothiophene, dimethyl- 4,4'-bipyridinium (MV2+), EDTA, and combined with ferredoxin-NADP reductase (FDR, E.C.18.104.22.168). The NADPH was generated by the FDR catalysis via the reduction of MV2+ by the photocatalysis of oligothiophene and EDTA as the sacrificial electron donor. As a result, the rate of the NADPH generation depended on the concentrations of nicotinamide adenine dinucleotide phosphate (NADP+) and MV2+. The effect of the intension of applied light showed the same tendency. Rate values of photoreduction of MV2+ and photogeneration of NADPH systems were investigated as a function of the concentration of MV2+. The production rates of methyl viologen radical cation (MV+) were a 1000- fold more than the NADPH production rates in the oligothiophenes. These results suggest that the electron transfer between FDR and its substrates is the rate-determining step.
ASJC Scopus subject areas
- Applied Microbiology and Biotechnology