8oxo2deossiguanosina

8-oxo-2'-deoxyguanosine, commonly abbreviated as 8-oxo-dG (also known as 8-oxodG), is a modified nucleoside that arises when the guanine base in DNA is oxidized. It is one of the most common forms of oxidative DNA damage and results from reactive oxygen species such as hydroxyl radicals. The lesion involves oxidation at the 8-position of guanine, producing 8-oxo-7,8-dihydroguanosine within the deoxyribonucleotide.

In DNA replication, 8-oxo-dG is mutagenic because it can pair with adenine as well as cytosine. When 8-oxo-dG pairs with cytosine, it can be repaired normally, but when mispaired with adenine, it often leads to G:C to T:A transversions if left unrepaired. The mutagenic potential makes 8-oxo-dG a useful indicator of oxidative stress and genomic instability.

Repair of 8-oxo-dG primarily occurs through base excision repair. The glycosylase enzyme OGG1 recognizes and excises 8-oxo-dG when paired with cytosine. If adenine is mispaired with 8-oxo-dG, the MUTYH glycosylase removes the mispaired adenine, allowing the correct cytosine to be restored after further repair synthesis and ligation. This coordinated repair helps maintain DNA sequence integrity in the face of oxidative damage.

8-oxo-dG is also used as a biomarker of oxidative stress. Levels can be measured in DNA or in biological fluids such as urine, and are studied in contexts like aging, cancer, and neurodegenerative diseases. Detection methods include high-performance liquid chromatography with electrochemical detection, liquid chromatography–mass spectrometry, and immunoassays.