In enzymology, a phylloquinone monooxygenase (2,3-epoxidizing) () is an enzyme that catalyzes the chemical reaction
The three substrates of this enzyme are phylloquinone, an electron acceptor AH<sub>2</sub>, and O<sub>2</sub>, whereas its three products are 2,3-epoxyphylloquinone, the reduction product A, and H<sub>2</sub>O.
This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O<sub>2</sub> as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derive from O miscellaneous. The systematic name of this enzyme class is . Other names in common use include , , , and .