Reaction: a nucleoside 5'-triphosphate + 2 H2O = a nucleoside 5'-phosphate + 2 phosphate (overall reaction)
(1a) a nucleoside 5'-triphosphate + H2O = a nucleoside 5'-diphosphate + phosphate
(1b) a nucleoside 5'-diphosphate + H2O = a nucleoside 5'-phosphate + phosphate
Other name(s): ATP-diphosphatase (ambiguous); adenosine diphosphatase; ADPase; ATP diphosphohydrolase [ambiguous]
Systematic name: nucleoside triphosphate phosphohydrolase (nucleoside monophosphoate-forming)
Comments: Apyrases are active against both di- and triphosphate nucleotides (NDPs and NTPs) and hydrolyse NTPs to nucleotide monophosphates (NMPs) in two distinct successive phosphate-releasing steps, with NDPs as intermediates. They differ from ATPases, which specifically hydrolyse ATP, by hydrolysing both ATP and ADP. The eukaryotic enzymes requires Ca2+, but Mg2+ can substitute. Most of the ecto-ATPases that occur on the cell surface and hydrolyse extracellular nucleotides belong to this enzyme family.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 9000-95-7
References:
1. Krishnan, P.S. Apyrase, pyrophosphatase and metaphosphatase of Penicillium chrysogenum. Arch. Biochem. Biophys. 37 (1952) 224-234. [PMID: 14953432]
2. Liébecq, C., Lallemand, A. and Degueldre-Guillaume, M.-J. [Partial purification and properties of potato apyrase.] Bull. Soc. Chim. Biol. 45 (1963) 573-594. [PMID: 13930517] (in French)
3. Chen, Y.R., Datta, N. and Roux, S.J. Purification and partial characterization of a calmodulin-stimulated nucleoside triphosphatase from pea nuclei. J. Biol. Chem. 262 (1987) 10689-10694. [PMID: 3038893]
4. Christoforidis, S., Papamarcaki, T., Galaris, D., Kellner, R. and Tsolas, O. Purification and properties of human placental ATP diphosphohydrolase. Eur. J. Biochem. 234 (1995) 66-74. [PMID: 8529670]
5. Wang, T.F. and Guidotti, G. CD39 is an ecto-(Ca2+,Mg2+)-apyrase. J. Biol. Chem. 271 (1996) 9898-9901. [PMID: 8626624]
6. Gao, X.D., Kaigorodov, V. and Jigami, Y. YND1, a homologue of GDA1, encodes membrane-bound apyrase required for Golgi N- and O-glycosylation in Saccharomyces cerevisiae. J. Biol. Chem. 274 (1999) 21450-21456. [PMID: 10409709]
7. Xu, W., Jones, C.R., Dunn, C.A. and Bessman, M.J. Gene ytkD of Bacillus subtilis encodes an atypical nucleoside triphosphatase member of the Nudix hydrolase superfamily. J. Bacteriol. 186 (2004) 8380-8384. [PMID: 15576788]