IUBMB Enzyme Nomenclature


Accepted name: 7-carboxy-7-deazaguanine synthase

Reaction: 6-carboxy-5,6,7,8-tetrahydropterin = 7-carboxy-7-carbaguanine + NH3

For diagram of reaction click here.

Glossary: 7-carboxy-7-carbaguanine = 7-carboxy-7-deazaguanine

Other name(s): 7-carboxy-7-carbaguanine synthase; queE (gene name)

Systematic name: 6-carboxy-5,6,7,8-tetrahydropterin ammonia-lyase

Comments: Requires Mg2+. The enzyme is a member of the superfamily of S-adenosyl-L-methionine-dependent radical (radical AdoMet) enzymes. Binds a [4Fe-4S] cluster that is coordinated by 3 cysteines and an exchangeable S-adenosyl-L-methionine molecule. The S-adenosyl-L-methionine is catalytic as it is regenerated at the end of the reaction. The reaction is part of the biosynthesis pathway of queuosine.

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


1. McCarty, R.M., Somogyi, A., Lin, G., Jacobsen, N.E. and Bandarian, V. The deazapurine biosynthetic pathway revealed: in vitro enzymatic synthesis of preQ0 from guanosine 5'-triphosphate in four steps. Biochemistry 48 (2009) 3847-3852. [PMID: 19354300]

2. McCarty, R.M., Krebs, C. and Bandarian, V. Spectroscopic, steady-state kinetic, and mechanistic characterization of the radical SAM enzyme QueE, which catalyzes a complex cyclization reaction in the biosynthesis of 7-deazapurines. Biochemistry 52 (2013) 188-198. [PMID: 23194065]

[EC created 2012]

Return to EC 4.3.99 home page
Return to EC 4.3 home page
Return to EC 4 home page
Return to Enzymes home page
Return to IUBMB Biochemical Nomenclature home page