<unk> s are a family of enzymes involved in base excision repair, classified under EC number EC 3.2.2. Base excision repair is the mechanism by which nucleotide residues in DNA with chemically altered nitrogen bases can be removed and replaced.<unk>  generates an apurinic or apyrimidinic site by removing the nitrogen base while leaving the sugar-phosphate backbone intact. These AP sites are recognised by AP endonuclease enzymes which complete the rest of the repair.
Some examples of<unk> s:
Ogg1 (yeast) or hOgg1 (humans) which removes 8-oxo-guanine, a type of modified nucleotide typically found after DNA is exposed to oxidative mutagens. See also OGG1.
uracil-DNA<unk> , found in prokaryotes and eukaryotes, which removes uracil from DNA.
DNA glycosylase
DNA polymerase
Deoxyribonuclease
Ligase
DNA polymerase I
Histone deacetylase
Restriction enzyme
RNA polymerase