IUBMB Enzyme Nomenclature


Accepted name: (d)CTP diphosphatase

Reaction: (1) CTP + H2O = CMP + diphosphate
(2) dCTP + H2O = dCMP + diphosphate

Other name(s): (d)CTP pyrophosphohydrolase; (d)CTP diphosphohydrolase; nudG (gene name)

Systematic name: (deoxy)cytidine 5'-triphosphate diphosphohydrolase

Comments: The enzyme, characterized from the bacterium Escherichia coli, is specific for the pyrimidine nucleotides CTP and dCTP. It also acts on 5-methyl-dCTP, 5-hydroxy-dCTP and 8-hydroxy-dGTP.

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


1. O'Handley, S.F., Dunn, C.A. and Bessman, M.J. Orf135 from Escherichia coli is a Nudix hydrolase specific for CTP, dCTP, and 5-methyl-dCTP. J. Biol. Chem. 276 (2001) 5421-5426. [PMID: 11053429]

2. Fujikawa, K. and Kasai, H. The oxidized pyrimidine ribonucleotide, 5-hydroxy-CTP, is hydrolyzed efficiently by the Escherichia coli recombinant Orf135 protein. DNA Repair (Amst.) 1 (2002) 571-576. [PMID: 12509230]

3. Kamiya, H., Iida, E. and Harashima, H. Important amino acids in the phosphohydrolase module of Escherichia coli Orf135. Biochem. Biophys. Res. Commun. 323 (2004) 1063-1068. [PMID: 15381107]

4. Iida, E., Satou, K., Mishima, M., Kojima, C., Harashima, H. and Kamiya, H. Amino acid residues involved in substrate recognition of the Escherichia coli Orf135 protein. Biochemistry 44 (2005) 5683-5689. [PMID: 15823026]

[EC created 2013]

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