IUBMB Enzyme Nomenclature


Accepted name: 2-amino-5-formylamino-6-ribosylaminopyrimidin-4(3H)-one 5'-monophosphate deformylase

Reaction: 2-amino-5-formylamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one + H2O = 2,5-diamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one + formate

Other name(s): ArfB

Systematic name: 2-amino-5-formylamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one amidohydrolase

Comments: The enzyme catalyses the second step in archaeal riboflavin and 7,8-didemethyl-8-hydroxy-5-deazariboflavin biosynthesis. The first step is catalysed by EC (GTP cyclohydrolase IIa). The bacterial enzyme, EC (GTP cyclohydrolase II) catalyses both reactions.

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


1. Grochowski, L.L., Xu, H. and White, R.H. An iron(II) dependent formamide hydrolase catalyzes the second step in the archaeal biosynthetic pathway to riboflavin and 7,8-didemethyl-8-hydroxy-5-deazariboflavin. Biochemistry 48 (2009) 4181-4188. [PMID: 19309161]

[EC created 2010, modified 2011]

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