IUBMB Enzyme Nomenclature


Accepted name: DNA-3'-diphospho-5'-guanosine diphosphatase

Reaction: [DNA]-3'-diphospho-5'-guanosine + H2O = [DNA]-3'-phosphate + GMP

Other name(s): aprataxin; DNA-3'pp5'G guanylate hydrolase; APTX (gene name); HNT3 (gene name)

Systematic name: [DNA]-3'-diphospho-5'-guanosine hydrolase (guanosine 5'-phosphate-forming)

Comments: Aprataxin is a DNA-binding protein that catalyses (among other activities) the 3' decapping of DNA-ppG (formed by EC, 3'-phosphate/5'-hydroxy nucleic acid ligase) [1]. The enzyme binds the guanylate group to a histidine residue at its active site, forming a covalent enzyme-nucleotide phosphate intermediate, followed by the hydrolysis of the guanylate from the nucleic acid and its eventual release. The enzyme also possesses the activity of EC, adenosine-5'-diphospho-5'-[DNA] diphosphatase, and EC, guanosine-5'-diphospho-5'-[DNA] diphosphatase.

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


1. Das, U., Chauleau, M., Ordonez, H. and Shuman, S. Impact of DNA3'pp5'G capping on repair reactions at DNA 3' ends. Proc. Natl. Acad. Sci. USA 111 (2014) 11317-11322. [PMID: 25049385]

2. Chauleau, M., Jacewicz, A. and Shuman, S. DNA3'pp5'G de-capping activity of aprataxin: effect of cap nucleoside analogs and structural basis for guanosine recognition. Nucleic Acids Res. 43 (2015) 6075-6083. [PMID: 26007660]

[EC created 2017 as EC, transferred 2019 to EC]

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