Reaction: (1) P1,P6-bis(5'-adenosyl)hexaphosphate + H2O = adenosine 5'-pentaphosphate + AMP
(2) P1,P5-bis(5'-adenosyl)pentaphosphate + H2O = adenosine 5'-tetraphosphate + AMP
Other name(s): hAps1; NUDT11 (gene name); hAps2; NUDT10 (gene name)
Systematic name: P1,P6-bis(5'-adenosyl)hexaphosphate nucleotidohydrolase (AMP-forming)
Comments: A divalent cation is essential for activity. Mn2+ (2-6 mM) is most effective. The enzyme controls intracellular levels of P1,P5-bis(5'-adenosyl)pentaphosphate and P1,P6-bis(5'-adenosyl)hexaphosphate. Weak activity with P1,P4-bis(5'-adenosyl)tetraphosphate. Marked preference for adenine over guanine nucleotides.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:
1. Leslie, N.R., McLennan, A.G. and Safrany, S.T. Cloning and characterisation of hAps1 and hAps2, human diadenosine polyphosphate-metabolising Nudix hydrolases. BMC Biochem 3 (2002) 20. [PMID: 12121577]
2. Safrany, S.T., Ingram, S.W., Cartwright, J.L., Falck, J.R., McLennan, A.G., Barnes, L.D. and Shears, S.B. The diadenosine hexaphosphate hydrolases from Schizosaccharomyces pombe and Saccharomyces cerevisiae are homologues of the human diphosphoinositol polyphosphate phosphohydrolase. Overlapping substrate specificities in a MutT-type protein. J. Biol. Chem. 274 (1999) 21735-21740. [PMID: 10419486]