Bifunctional oxidoreductase ables to act both on prenyl naphthoquinones and on prenyl benzoquinones (PubMed:21844348, PubMed:26023160). May serve a respiratory function (PubMed:12972666). Involved in an electron flow toward the plastoglobule plastoquinone pool (PubMed:21844348, PubMed:25018761). Required for plastochromanol-8 accumulation and for phylloquinone (vitamin K1) production (PubMed:21844348, PubMed:25018761). Probably not directly involved in cyclic or chlororespiratory electron flows under standard growth conditions, but participates in the redox metabolism of plastoquinone-9 and the tocophrol recycling-intermediate alpha-tocopherol quinone (PubMed:21844348, PubMed:25018761). Catalyzes the penultimate step in the biosynthesis of vitamin K1 (PubMed:26023160). a quinone + H(+) + NADH = a quinol + NAD(+) a ubiquinone + H(+) + NADH = a ubiquinol + NAD(+) demethylphylloquinone + H(+) + NADPH = demethylphylloquinol + NADP(+) Binds 1 FAD per subunit. Inhibited by dicumarol. kcat is 0.44 sec(-1) for menadione. Flowers, roots, leaves and stems. Up-regulated by high-light. No visible phenotype (PubMed:21844348, PubMed:25018761). Increased photosensitivity to high light (PubMed:26023160). Belongs to the NADH dehydrogenase family. Extended C-terminus.