IUBMB Enzyme Nomenclature


Accepted name: flavone synthase I

Reaction: a flavanone + 2-oxoglutarate + O2 = a flavone + succinate + CO2 + H2O

For diagram of reaction click here or click here.

Other name(s): FNSI (gene name)

Systematic name: flavanone,2-oxoglutarate:oxygen oxidoreductase (dehydrating)

Comments: The enzyme, which has been found in rice and in members of the Apiaceae (a plant family), is a member of the 2-oxoglutarate-dependent dioxygenases, and requires ascorbate and Fe2+ for full activity.

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


1. Martens, S., Forkmann, G., Matern, U. and Lukačin, R. Cloning of parsley flavone synthase I. Phytochemistry 58 (2001) 43-46. [PMID: 11524111]

2. Lukačin, R., Matern, U., Junghanns, K.T., Heskamp, M.L., Britsch, L., Forkmann, G. and Martens, S. Purification and antigenicity of flavone synthase I from irradiated parsley cells. Arch. Biochem. Biophys. 393 (2001) 177-183. [PMID: 11516175]

3. Martens, S., Forkmann, G., Britsch, L., Wellmann, F., Matern, U. and Lukačin, R. Divergent evolution of flavonoid 2-oxoglutarate-dependent dioxygenases in parsley. FEBS Lett. 544 (2003) 93-98. [PMID: 12782296]

[EC created 2004 as EC, transferred 2018 to EC]

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