Specifically hydrolyzes both 8-oxo-deoxyguanosine triphosphate (8-oxo-dGTP) and 8-oxo-guanosine triphosphate (8-oxo-GTP) to the related monophosphates, thereby cleaning up the nucleotide pools and preventing misincorporation of 8-oxoGua into DNA and RNA. It prevents replicational errors by removing an oxidatively damaged form of guanine (8-oxo-dGTP) from DNA and the nucleotide pool. 8-oxo-dGTP can be inserted opposite dA and dC residues of template DNA with almost equal efficiency thus leading to A.T to G.C transversions. 8-oxo-dGTP + H2O = 8-oxo-dGMP + diphosphate + H(+) 8-oxo-GTP + H2O = 8-oxo-GMP + diphosphate + H(+) Belongs to the Nudix hydrolase family.