8-Hydroxydeoxyguanosine: Not mere biomarker for oxidative stress, but remedy for oxidative stress-implicated gastrointestinal diseases

Figure 2 Generation and metabolism of 8-hydroxydeoxyguanosine. 8-oxoguanine DNA glycosylase 1 (OGG1) is a DNA glycosylase enzyme involved in base excision repair (BER), and is the primary enzyme responsible for excision of 7,7-dihydro-8-oxoguanine that occurs as a result of exposure to reactive oxygen species (ROS). OGG1 is a bifunctional glycosylase, because it is able to both cleave the glycosidic bond of the mutagenic lesion, and cause strand breakage in the DNA backbone. Nucleotide excision repair (NER) is a DNA repair mechanism, which is a particularly important mechanism by which the cell can prevent unwanted mutations by removing the vast majority of ROS-induced DNA damage.