Mediates the hydrolysis of some nucleoside diphosphate derivatives. Can degrade 8-oxo-dGTP in vitro, suggesting that it may remove an oxidatively damaged form of guanine (7,8-dihydro-8- oxoguanine) from DNA and the nucleotide pool, thereby preventing misincorporation of 8-oxo-dGTP into DNA thus preventing A:T to C:G transversions. Its substrate specificity in vivo however remains unclear. May have a role in DNA synthesis and cell cycle progression through the interaction with PCNA.