IUBMB Enzyme Nomenclature


Accepted name: fraxetin 5-hydroxylase

Reaction: fraxetin + [reduced NADPH—hemoprotein reductase] + O2 = sideretin (reduced form) + [oxidized NADPH—hemoprotein reductase] + H2O

Glossary: fraxetin = 7,8-dihydroxy-6-methoxy-2H-chromen-2-one
sideretin (reduced form) = 5,7,8-trihydroxy-6-methoxy-2H-chromen-2-one

Other name(s): CYP82C4; fraxetin 5-monooxygenase

Systematic name: fraxetin,[reduced NADPH—hemoprotein reductase]:oxygen oxidoreductase (5-hydroxylating)

Comments: A cytochrome P-450 (heme-thiolate) protein involved in biosynthesis of iron(III)-chelating coumarins in higher plants.

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


1. Rajniak, J., Giehl, R.FH., Chang, E., Murgia, I., von Wiren, N. and Sattely, E.S. Biosynthesis of redox-active metabolites in response to iron deficiency in plants. Nat. Chem. Biol. 14 (2018) 442-450. [PMID: 29581584]

[EC created 2018]

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