IUBMB Enzyme Nomenclature


Accepted name: 3-hydroxyindolin-2-one monooxygenase

Reaction: 3-hydroxyindolin-2-one + [reduced NADPH—hemoprotein reductase] + O2 = 2-hydroxy-2H-1,4-benzoxazin-3(4H)-one [oxidized NADPH—hemoprotein reductase] + H2O

For diagram of reaction click here.

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

Other name(s): BX4 (gene name); CYP71C1 (gene name)

Systematic name: 3-hydroxyindolin-2-one,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (2-hydroxy-2H-1,4-benzoxazin-3(4H)-one-forming)

Comments: A cytochrome P-450 (heme-thiolate) protein. The enzyme is involved in the biosynthesis of protective and allelophatic benzoxazinoids in some plants, most commonly from the family of Poaceae (grasses).

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


1. 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]

2. Frey, M., Chomet, P., Glawischnig, E., Stettner, C., Grün, S., Winklmair, A., Eisenreich, W., Bacher, A., Meeley, R.B., Briggs, S.P., Simcox, K. and Gierl, A. Analysis of a chemical plant defense mechanism in grasses. Science 277 (1997) 696-699. [PMID: 9235894]

3. Spiteller, P., Glawischnig, E., Gierl, A. and Steglich, W. Studies on the biosynthesis of 2-hydroxy-1,4-benzoxazin-3-one (HBOA) from 3-hydroxyindolin-2-one in Zea mays. Phytochemistry 57 (2001) 373-376. [PMID: 11393516]

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