EC Explorer

3.6.1.71

adenosine-5′-diphospho-5′-[DNA] diphosphatase

(1) adenosine-5′-diphospho-5′-[DNA] + H₂O = AMP + phospho-5′-[DNA];;(2) adenosine-5′-diphospho-5′-(ribonucleotide)-[DNA] + H₂O = AMP + 5′-phospho-(ribonucleotide)-[DNA]

aprataxin, 5′-App5′-DNA adenylate hydrolase, APTX (gene name), HNT3 (gene name)

adenosine-5′-diphospho-5′-[DNA] hydrolase (adenosine 5′-phosphate-forming)

Aprataxin is a DNA-binding protein involved in different types of DNA break repair. The enzyme acts (among other activities) on abortive DNA ligation intermediates that contain an adenylate covalently linked to the 5′-phosphate DNA terminus. It also acts when the adenylate is covalently linked to the 5′-phosphate of a ribonucleotide linked to a DNA strand, which is the result of abortive ligase activty on products of EC 3.1.26.4, ribonuclease H, an enzyme that cleaves RNA-DNA hybrids on the 5′ side of the ribonucleotide found in the 5′-RNA-DNA-3′ junction. Aprataxin binds the adenylate group to a histidine residue within the active site, followed by its hydrolysis from the nucleic acid and eventual release, leaving a 5′-phosphate terminus that can be efficiently rejoined. The enzyme also possesses the activities of EC 3.6.1.70, guanosine-5′-diphospho-5′-[DNA] diphosphatase, and EC 3.6.1.72, DNA-3′-diphospho-5′-guanosine diphosphatase.

created 2017 as EC 3.1.11.7, transferred 2019 to EC 3.6.1.71