Nucleotides are involved in numerous biochemical reactions and pathways within the cell as substrates, cofactors, and effectors. Nudix hydrolases, such as NUDT12 (Nudix (nucleoside diphosphate linked moiety X)-type motif 12), regulate the concentrations of individual nucleotides and of nucleotide ratios in response to changing circumstances. NUDT12 hydrolyzes NAD(P)H to NMNH and AMP (2',5'-ADP), and diadenosine diphosphate to AMP. It also has moderate activity towards NAD(P)(+), ADP-ribose and diadenosine triphosphate. It may regulate the concentration of peroxisomal nicotinamide nucleotide cofactors required for oxidative metabolism.