GO:0047058:   vitamin-K-epoxide reductase (warfarin-insensitive) activity
Catalysis of the reaction: 3-hydroxy-2-methyl-3-phytyl-2,3-dihydronaphthoquinone + oxidized dithiothreitol + H2O = 2,3-epoxy-2,3-dihydro-2-methyl-3-phytyl-1,4-naphthoquinone + 1,4-dithiothreitol.