EC Explorer

1.14.13.117

isoleucine N-monooxygenase

L-isoleucine + 2 O₂ + 2 NADPH + 2 H⁺ = (E)-2-methylbutanal oxime + 2 NADP⁺ + CO₂ + 3 H₂O (overall reaction);;(1a) L-isoleucine + O₂ + NADPH + H⁺ = N-hydroxy-L-isoleucine + NADP⁺ + H₂O;;(1b) N-hydroxy-L-isoleucine + O₂ + NADPH + H⁺ = N,N-dihydroxy-L-isoleucine + NADP⁺ + H₂O;;(1c) N,N-dihydroxy-L-isoleucine = (E)-2-methylbutanal oxime + CO₂ + H₂O (spontaneous)

CYP79D3, CYP79D4

L-isoleucine,NADPH:oxygen oxidoreductase (N-hydroxylating)

A heme-thiolate protein (P-450). This enzyme catalyses two successive N-hydroxylations of L-isoleucine, the first committed steps in the biosynthesis of the cyanogenic glucoside lotaustralin in the plant Lotus japonicus. The product of the two hydroxylations, N,N-dihydroxy-L-isoleucine, is extremely labile and dehydrates spontaneously. The dehydrated product is then subject to a decarboxylation that produces the oxime. It is still not known whether the decarboxylation is spontaneous or catalysed by the enzyme. The product, (E)-2-methylbutanal oxime, undergoes a spontaneous isomerization to the (Z) form. The enzyme can also accept L-valine as substrate, with a lower activity. It is different from EC 1.14.13.118 (valine N-monooxygenase), which prefers L-valine.

created 2010, deleted 2017