Endonuclease III homolog 1
Saccharomyces cerevisiae (strain ATCC 204508 / S288c)
Bifunctional DNA N-glycosylase with associated apurinic/apyrimidinic (AP) lyase function that catalyzes the first step in base excision repair (BER), the primary repair pathway for the repair of oxidative DNA damage. The DNA N-glycosylase activity releases the damaged DNA base from DNA by cleaving the N-glycosidic bond, leaving an AP site. The AP-lyase activity cleaves the phosphodiester bond 3' to the AP site by a beta-elimination. Primarily recognizes and repairs oxidative base damage of pyrimidines, but also purine-derived lesions, alkylation damage and cytosine photoproducts generated by UV irradiation as well as abasic sites. Has also 8-oxoguanine DNA glycosylase activity. The AP lyase can incise AP sites opposite all four bases. May also play a role in the regulation of mtDNA copy number by introducing a double-stranded break (DSB) at the mtDNA replication origin ori5, initiating the rolling-circle mtDNA replication.
Belongs to the Nth/MutY family.