Posted in Research

KEGG ENZYME: 1.14.14.39

 October 2, 2021

Entry
EC 1.14.14.39               Enzyme                                 
Name

isoleucine N-monooxygenase;
CYP79D3 (gene name);
CYP79D4 (gene name)

Class

Oxidoreductases;
Acting on paired donors, with incorporation or reduction of molecular oxygen;
With reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen into the other donor

Sysname

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

Reaction(IUBMB)
L-isoleucine + 2 [reduced NADPH—hemoprotein reductase] + 2 O2 = (1E,2S)-2-methylbutanal oxime + 2 [oxidized NADPH—hemoprotein reductase] + CO2 + 3 H2O (overall reaction) [RN:R09403];
(1a) L-isoleucine + [reduced NADPH—hemoprotein reductase] + O2 = N-hydroxy-L-isoleucine + [oxidized NADPH—hemoprotein reductase] + H2O [RN:R10027];
(1b) N-hydroxy-L-isoleucine + [reduced NADPH—hemoprotein reductase] + O2 = N,N-dihydroxy-L-isoleucine + [oxidized NADPH—hemoprotein reductase] + H2O [RN:R10028];
(1c) N,N-dihydroxy-L-isoleucine = (1E,2S)-2-methylbutanal oxime + CO2 + H2O (spontaneous) [RN:R10029]
Reaction(KEGG) Substrate
L-isoleucine [CPD:C00407];
[reduced NADPH—hemoprotein reductase] [CPD:C03024];
O2 [CPD:C00007];
N-hydroxy-L-isoleucine [CPD:C20310];
N,N-dihydroxy-L-isoleucine [CPD:C20311]
Product
(1E,2S)-2-methylbutanal oxime;
[oxidized NADPH—hemoprotein reductase] [CPD:C03161];
CO2 [CPD:C00011];
H2O [CPD:C00001];
N-hydroxy-L-isoleucine [CPD:C20310];
N,N-dihydroxy-L-isoleucine [CPD:C20311]
Comment
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.
History

EC 1.14.14.39 created 2010 as EC 1.14.13.117, transferred 2017 to EC 1.14.14.39

Pathway
ec00460   Cyanoamino acid metabolism
ec00966   Glucosinolate biosynthesis
ec01110   Biosynthesis of secondary metabolites
Orthology
K14984   isoleucine N-monooxygenase
Genes Reference   Authors

Andersen MD, Busk PK, Svendsen I, Moller BL

  Title

Cytochromes P-450 from cassava (Manihot esculenta Crantz) catalyzing the first steps in the biosynthesis of the cyanogenic glucosides linamarin and lotaustralin. Cloning, functional expression in Pichia pastoris, and substrate specificity of the isolated recombinant enzymes.

  Journal Reference   Authors

Forslund K, Morant M, Jorgensen B, Olsen CE, Asamizu E, Sato S, Tabata S, Bak S

  Title

Biosynthesis of the nitrile glucosides rhodiocyanoside A and D and the cyanogenic glucosides lotaustralin and linamarin in Lotus japonicus.

  Journal   Sequence Other DBs
ExPASy – ENZYME nomenclature database:  1.14.14.39

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