Base excision repair is the critical machinery which corrects DNA lesions and ensures that mutations are not propagated. The process of base excision repair is achieved via specific and sequential enzyme activity. Damaged bases are first identified and removed by DNA glycosylases/AP lyases, which break beta-N glycosidic bonds to create an abasic (AP) DNA site. Depending on the initial events of base removal, repair proceeds through either the short patch (1 nucleotide) or long patch (2-10 nucleotides) repair pathways. This involves the AP site being recognized by endonucleases which nick the damaged DNA, and recruit DNA polymerases to fill the gap in the DNA. Finally, base excision repair is complete when the new DNA strand is sealed by DNA ligase. R&D Systems offers quality base excision repair products which include DNA glycosidases, endonucleases, polymerases, and more.