IUBMB Enzyme Nomenclature


Accepted name: 2-hydroxy-1,4-benzoxazin-3-one monooxygenase

Reaction: 2-hydroxy-2H-1,4-benzoxazin-3(4H)-one + NAD(P)H + H+ + O2 = 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one + NAD(P)+ + H2O

For diagram of reaction click here.

Glossary: 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one = DIBOA
2-hydroxy-2H-1,4-benzoxazin-3(4H)-one = HBOA

Other name(s): BX5 (gene name); CYP71C3 (gene name)

Systematic name: 2-hydroxy-2H-1,4-benzoxazin-3(4H)-one,NAD(P)H:oxygen oxidoreductase (N-hydroxylating)

Comments: The enzyme is involved in the biosynthesis of protective and allelophatic benzoxazinoids in some plants, most commonly from the family of Poaceae (grasses). It is a member of the cytochrome P450 dependent monooxygenases.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:


1. Bailey, B.A. and Larson, R.L. Maize microsomal benzoxazinone N-monooxygenase. Plant Physiol. 95 (1991) 792-796. [PMID: 16668055]

2. Glawischnig, E., Grun, S., Frey, M. and Gierl, A. Cytochrome P450 monooxygenases of DIBOA biosynthesis: specificity and conservation among grasses. Phytochemistry 50 (1999) 925-930. [PMID: 10385992]

[EC created 2012]

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