valine N-monooxygenase [EC:1.14.14.38]

PMID:16126856

Jorgensen K, Bak S, Busk PK, Sorensen C, Olsen CE, Puonti-Kaerlas J, Moller BL

Cassava plants with a depleted cyanogenic glucoside content in leaves and tubers. Distribution of cyanogenic glucosides, their site of synthesis and transport, and blockage of the biosynthesis by RNA interference technology.

Plant Physiol 139:363-74 (2005)
DOI:10.1104/pp.105.065904

[ag:AAV97888 AAV97889]

PMID:10636899

Andersen MD, Busk PK, Svendsen I, Moller BL

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.

J Biol Chem 275:1966-75 (2000)
DOI:10.1074/jbc.275.3.1966

[ag:AAF27289 AAF27290]

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

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

L-valine + 2 [reduced NADPH---hemoprotein reductase] + 2 O2 = (E)-2-methylpropanal oxime + 2 [oxidized NADPH---hemoprotein reductase] + CO2 + 3 H2O (overall reaction) [RN:R08663];
(1a) L-valine + [reduced NADPH---hemoprotein reductase] + O2 = N-hydroxy-L-valine + [oxidized NADPH---hemoprotein reductase] + H2O [RN:R10031];
(1b) N-hydroxy-L-valine + [reduced NADPH---hemoprotein reductase] + O2 = N,N-dihydroxy-L-valine + [oxidized NADPH---hemoprotein reductase] + H2O [RN:R10032];
(1c) N,N-dihydroxy-L-valine = (E)-2-methylpropanal oxime + CO2 + H2O [RN:R10033]

R08663 R10031 R10032 R10033;
(other) R10027 R10028 R10029

L-valine [CPD:C00183];
[reduced NADPH---hemoprotein reductase] [CPD:C03024];
O2 [CPD:C00007];
N-hydroxy-L-valine [CPD:C20313];
N,N-dihydroxy-L-valine [CPD:C20314]

A cytochrome P-450 (heme-thiolate) protein. This enzyme catalyses two successive N-hydroxylations of L-valine, the committed step in the biosynthesis of the cyanogenic glucoside linamarin in Manihot esculenta (cassava). The product of the two hydroxylations, N,N-dihydroxy-L-valine, is labile and undergoes dehydration and decarboxylation that produce the (E) isomer of the oxime. It is still not known whether the decarboxylation is spontaneous or catalysed by the enzyme. The enzyme can also accept L-isoleucine as substrate, with a lower activity. It is different from EC 1.14.14.39, isoleucine N-monooxygenase, which prefers L-isoleucine.

EC 1.14.14.38 created 2010 as EC 1.14.13.118, transferred 2017 to EC 1.14.14.38

1  [PMID:10636899]

Andersen MD, Busk PK, Svendsen I, Moller BL

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.

J. Biol. Chem. 275 (2000) 1966-75.

[ag:AAF27289 AAF27290]

2  [PMID:15122013]

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

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

Plant. Physiol. 135 (2004) 71-84.