IUBMB Enzyme Nomenclature


Accepted name: flavanone 3-dioxygenase

Reaction: a (2S)-flavan-4-one + 2-oxoglutarate + O2 = a (2R,3R)-dihydroflavonol + succinate + CO2

For diagram of reaction click here and mechanism click here.

Other name(s): naringenin 3-hydroxylase; flavanone 3-hydroxylase; flavanone 3β-hydroxylase; flavanone synthase I; (2S)-flavanone 3-hydroxylase; naringenin,2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating); F3H; flavanone,2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating)

Systematic name: (2S)-flavan-4-one,2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating)

Comments: Requires Fe2+ and ascorbate. This plant enzyme catalyses an early step in the flavonoid biosynthesis pathway, leading to the production of flavanols and anthocyanins. Substrates include (2S)-naringenin, (2S)-eriodictyol, (2S)-dihydrotricetin and (2S)-pinocembrin. Some enzymes are bifuctional and also catalyse EC, flavonol synthase.

Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 75991-43-4


1. Forkmann, G., Heller, W. and Grisebach, H. Anthocyanin biosynthesis in flowers of Matthiola incana flavanone 3- and flavonoid 3'-hydroxylases. Z. Naturforsch. C: Biosci. 35 (1980) 691-695.

2. Charrier, B., Coronado, C., Kondorosi, A. and Ratet, P. Molecular characterization and expression of alfalfa (Medicago sativa L.) flavanone-3-hydroxylase and dihydroflavonol-4-reductase encoding genes. Plant Mol. Biol. 29 (1995) 773-786. [PMID: 8541503]

3. Pelletier, M.K. and Shirley, B.W. Analysis of flavanone 3-hydroxylase in Arabidopsis seedlings. Coordinate regulation with chalcone synthase and chalcone isomerase. Plant Physiol. 111 (1996) 339-345. [PMID: 8685272]

4. Wellmann, F., Matern, U. and Lukačin, R. Significance of C-terminal sequence elements for Petunia flavanone 3β-hydroxylase activity. FEBS Lett. 561 (2004) 149-154. [PMID: 15013767]

5. Jin, Z., Grotewold, E., Qu, W., Fu, G. and Zhao, D. Cloning and characterization of a flavanone 3-hydroxylase gene from Saussurea medusa. DNA Seq 16 (2005) 121-129. [PMID: 16147863]

6. Shen, G., Pang, Y., Wu, W., Deng, Z., Zhao, L., Cao, Y., Sun, X. and Tang, K. Cloning and characterization of a flavanone 3-hydroxylase gene from Ginkgo biloba. Biosci Rep 26 (2006) 19-29. [PMID: 16779664]

[EC created 1983, modified 1989, modified 2004, modified 2016]

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