NUDIX hydrolase type 5 (NUDT5) is a kind of ADP-ribose pyrophosphatase and nucleotide metabolizing enzyme that can either act as an ADP-sugar pyrophosphatase in absence of diphosphate or catalyze the synthesis of ATP in presence of diphosphate. In absence of diphosphate, NUDT5 hydrolyzes with similar activities various modified nucleoside diphosphates such as ADP-ribose, ADP-mannose, ADP-glucose, 8-oxo-GDP and 8-oxo-dGDP. In presence of diphosphate, NUDT5 mediates the synthesis of ATP in the nucleus by catalyzing the conversion of ADP-ribose to ATP and ribose 5-phosphate.