The function of NUDT13 (nudix hydrolase 13, Ensembl gene identifier ENSG00000166321) is as follows. NAD(P)H pyrophosphatase that hydrolyzes NADH into NMNH and AMP, and NADPH into NMNH and 2',5'-ADP. Has a marked preference for the reduced pyridine nucleotides. Does not show activity toward NAD-capped RNAs; the NAD-cap is an atypical cap present at the 5'-end of some RNAs. .