Reaction paths starting from the products (PPPi and dG) released by the catalytic action of Dgt yielding spectrophotometrically detectable compounds. Upper path, the tripolyphosphate (PPPi) produced by Dgt is hydrolyzed by alkaline phosphatase (AP), yielding orthophosphate (Pi), which, in the presence of inosine and PNPase, is converted to ribose-1-phosphate and hypoxanthine. Finally, hypoxanthine is oxidized by XOD, yielding uric acid. Lower path, the deoxyguanosine released by Dgt is phosphorolysed by PNPase, producing deoxyribose-1-phosphate and guanine. Guanine is then converted by XOD into 8-oxoguanine.