APTX is a DNA-binding protein which participates in single-strand DNA break repair, double-strand DNA break repair and base excision repair. APTX determines abortive DNA ligation intermediates created each at base excision sites, or while DNA ligases attempt to restore non-ligatable breaks induced by reactive oxygen species. APTX catalyzes the release of adenylate groups covalently linked to 5-phosphate termini, resulting in the production of 5-phosphate termini that can be efficiently rejoined. APTX hydrolyzes adenosine 5-monophosphoramidate (AMP-NH(2)) and diadenosine tetraphosphate (AppppA), but with lower catalytic activity Synonyms: AXA1, AOA, FHA-HIT, AOA11, ataxia 1, early onset with hypoalbuminemia1 EOAHA1, EAOH1, Forkhead-associated domain histidine triad-like protein, APTX, Aprataxin, AOA1, EAOH, EOAHA, MGC1072, FLJ20157