Tags: Protein.
DNA-(apurinic or apyrimidinic site) lyase is an enzyme that in humans is encoded by the APEX1 gene.Apurinic/apyrimidinic (AP) sites (also called abasic sites) occur frequently in DNA molecules by spontaneous hydrolysis by DNA damaging agents or by DNA glycosylases that remove specific abnormal bases. AP sites are pre-mutagenic lesions that can prevent normal DNA replication. All cells from simple prokaryotes to humans have evolved systems to identify and repair such sites.