IUBMB Enzyme Nomenclature


Accepted name: 7,8-didemethyl-8-hydroxy-5-deazariboflavin synthase

Reaction: 5-amino-5-(4-hydroxybenzyl)-6-(D-ribitylimino)-5,6-dihydrouracil + S-adenosyl-L-methionine = 7,8-didemethyl-8-hydroxy-5-deazariboflavin + NH3 + L-methionine + 5'-deoxyadenosine

For diagram of reaction click here.

Glossary: 7,8-didemethyl-8-hydroxy-5-deazariboflavin = Fo

Other name(s): Fo synthase; fbiC (gene name) (ambiguous); cofG (gene name)

Systematic name: 5-amino-5-(4-hydroxybenzyl)-6-(D-ribitylimino)-5,6-dihydrouracil ammonia-lyase (7,8-didemethyl-8-hydroxy-5-deazariboflavin-forming)

Comments: The enzyme produces the Fo precursor of the redox cofactor coenzyme F420, which is found in methanogens and in various actinobacteria. Fo is also produced by some cyanobacteria and eukaryotes. The enzyme, which forms a complex with EC, 5-amino-6-(D-ribitylamino)uracil—L-tyrosine 4-hydroxyphenyl transferase, is a radical SAM enzyme that uses the 5'-deoxyadenosyl radical to catalyse the condensation reaction.

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


1. Decamps, L., Philmus, B., Benjdia, A., White, R., Begley, T.P. and Berteau, O. Biosynthesis of F0, precursor of the F420 cofactor, requires a unique two radical-SAM domain enzyme and tyrosine as substrate. J. Am. Chem. Soc. 134 (2012) 18173-18176. [PMID: 23072415]

2. Philmus, B., Decamps, L., Berteau, O. and Begley, T.P. Biosynthetic versatility and coordinated action of 5'-deoxyadenosyl radicals in deazaflavin biosynthesis. J. Am. Chem. Soc. 137 (2015) 5406-5413. [PMID: 25781338]

[EC created 2010 as EC, part transferred 2018 to EC]

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