IUBMB Enzyme Nomenclature


Accepted name: 6-carboxytetrahydropterin synthase

Reaction: 7,8-dihydroneopterin 3'-triphosphate + H2O = 6-carboxy-5,6,7,8-tetrahydropterin + acetaldehyde + triphosphate

Glossary: 7,8-dihydroneopterin 3'-triphosphate = 2-amino-6-[(1S,2R)-1,2-dihydroxy-3-triphosphooxypropyl]-4-oxo-2,3,7,8-tetrahydropteridine
For diagram of reaction click here.

6-carboxy-5,6,7,8-tetrahydropterin = 2-amino-4-oxo-2,3,5,6,7,8-hexahydropteridine-6-carboxylate

Other name(s): CPH4 synthase; queD (gene name); ToyB; ykvK (gene name)

Systematic name: 7,8-dihydroneopterin 3'-triphosphate acetaldehyde-lyase (6-carboxy-5,6,7,8-tetrahydropterin and triphosphate-forming)

Comments: Binds Zn2+. Isolated from the bacteria Bacillus subtilis and Escherichia coli. The reaction is part of the biosynthesis pathway of queuosine.The enzyme from Escherichia coli can also convert 6-pyruvoyl-5,6,7,8-tetrahydropterin and sepiapterin to 6-carboxy-5,6,7,8-tetrahydropterin [2].

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


1. Cicmil, N. and Shi, L. Crystallization and preliminary X-ray characterization of queD from Bacillus subtilis, an enzyme involved in queuosine biosynthesis. Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun. 64 (2008) 119-122. [PMID: 18259064]

2. McCarty, R.M., Somogyi, A. and Bandarian, V. Escherichia coli QueD is a 6-carboxy-5,6,7,8-tetrahydropterin synthase. Biochemistry 48 (2009) 2301-2303. [PMID: 19231875]

[EC created 2012]

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