In enzymology, a lysine 2-monooxygenase (EC 1.13.12.2) is an enzyme that catalyzes the chemical reaction

L-lysine + O₂ ${\displaystyle \rightleftharpoons }$ 5-aminopentanamide + CO₂ + H₂O

Thus, the two substrates of this enzyme are L-lysine and O₂, whereas its 3 products are 5-aminopentanamide, CO₂, and H₂O.

This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O₂ as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases). The oxygen incorporated need not be derived from O with incorporation of one atom of oxygen (internal monooxygenases o internal mixed-function oxidases). The systematic name of this enzyme class is L-lysine:oxygen 2-oxidoreductase (decarboxylating). Other names in common use include lysine oxygenase, lysine monooxygenase, and L-lysine-2-monooxygenase. This enzyme participates in lysine degradation. It employs one cofactor, FAD.