Multifunctional human Apurinic/Apyrimidinic endonuclease 1: role of additional functions

Human apurinic/apyrimidinic (AP) endonuclease 1 (APE1) is a multifunctional enzyme involved in base excision repair (BER). APE I cleaves DNA 5' of an AP site to produce a single-strand break with 5'-OH and 3'-deoxyribose phosphate. In addition to its AP-endonucleolytic function, APE I possesses 3'-phosphodiesterase, 3'-5' exonuclease, and 3'-phosphatase activities. Independently of its function as a repair protein, APE1 was identified as a redox factor (Ref-1). The review summarizes the published and original data on the role of the additional functions of APE1 in DNA repair and apoptosis and regulation of the BER system via APE1 interaction with DNA and other repair proteins.