Valine N-monooxygenase (EC 1.14.13.118, CYP79D1, CYP79D2) is an enzyme with systematic name L-valine,NADPH:oxygen oxidoreductase (N-hydroxylating).^[1][2] This enzyme catalyses the following chemical reaction

L-valine + 2 O₂ + 2 NADPH + 2 H⁺ ${\displaystyle \rightleftharpoons }$ (E)-2-methylpropanal oxime + 2 NADP⁺ + CO₂ + 3 H₂O (overall reaction)

(1a) L-valine + O₂ + NADPH + H⁺ ${\displaystyle \rightleftharpoons }$ N-hydroxy-L-valine + NADP⁺ + H₂O

(1b) N-hydroxy-L-valine + O2 + NADPH + H⁺ ${\displaystyle \rightleftharpoons }$ N,N-dihydroxy-L-valine + NADP⁺ + H₂O

(1c) N,N-dihydroxy-L-valine ${\displaystyle \rightleftharpoons }$ (E)-2-methylpropanal oxime + CO₂ + H₂O (spontaneous reaction)

Valine N-monooxygenase is a heme-thiolate protein (P-450).