EC Explorer

1.14.14.39

isoleucine N-monooxygenase

L-isoleucine + 2 [reduced NADPH—hemoprotein reductase] + 2 O₂ = (1E,2S)-2-methylbutanal oxime + 2 [oxidized NADPH—hemoprotein reductase] + CO₂ + 3 H₂O (overall reaction);;(1a) L-isoleucine + [reduced NADPH—hemoprotein reductase] + O₂ = N-hydroxy-L-isoleucine + [oxidized NADPH—hemoprotein reductase] + H₂O;;(1b) N-hydroxy-L-isoleucine + [reduced NADPH—hemoprotein reductase] + O₂ = N,N-dihydroxy-L-isoleucine + [oxidized NADPH—hemoprotein reductase] + H₂O;;(1c) N,N-dihydroxy-L-isoleucine = (1E,2S)-2-methylbutanal oxime + CO₂ + H₂O (spontaneous)

CYP79D3 (gene name), CYP79D4 (gene name)

L-isoleucine,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (N-hydroxylating)

This cytochrome P-450 (heme-thiolate) enzyme, found in plants, catalyses two successive N-hydroxylations of L-isoleucine, the committed step in the biosynthesis of the cyanogenic glucoside lotaustralin. The product of the two hydroxylations, N,N-dihydroxy-L-isoleucine, is labile and undergoes dehydration followed by decarboxylation, producing the oxime. It is still not known whether the decarboxylation is spontaneous or catalysed by the enzyme. The enzyme can also accept L-valine, but with a lower activity. cf. EC 1.14.14.38, valine N-monooxygenase.

created 2010 as EC 1.14.13.117, transferred 2017 to EC 1.14.14.39