Stereospecificity of hydride transfer and substrate specificity for FMN-containing NAD(P)H-flavin oxidoreductase from the luminescent bacterium, Vibrio fischeri ATCC 7744.

The stereospecificity of the hydride transfer in NAD(P)H-flavin reductase reaction of V. fischeri ATCC 7744 was determined by 1H-NMR spectroscopy using stereospecifically labeled reduced beta-nicotinamide adenine dinucleotide (beta-NADH). The recombinant flavoenzyme, purified from E. coli cells, selectively transferred the pro-R hydrogen at the C-4 position of the nicotinamide ring to flavin and is therefore classified as an A-side specific enzyme. Lumiflavin was used for the reductase reaction, but lumichrome and alpha-NADH were not utilized as electron acceptor and donor, respectively.