Molecular function

AP site-DNA 5'-phosphomonoester-lyase activity, DNA-(apurinic or apyrimidinic site) 5'-phosphomonoester-lyase activity, DNA-(apurinic or apyrimidinic site) lyase activity, class I DNA-(apurinic or apyrimidinic site) lyase activity

Catalysis of the cleavage of an AP site 3' of the baseless site by a beta-lyase mechanism, leaving an unsaturated aldehyde, termed a 3'-(4-hydroxy-5-phospho-2-pentenal) residue, and a 5'-phosphate.

AP endonuclease class I activity, AP lyase activity, class I AP endonuclease activity

Note that this term is does not have parentage in the 'nuclease activity' branch of the ontology because both GO and the Enzyme Commission define nuclease activity as a type of hydrolysis. Class II AP endonuclease is a nuclease, but not Class I, III and IV.