APEX2 - DNA-(apurinic or apyrimidinic site) lyase 2 - human protein (Function)
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APEX2 »  DNA-(apurinic or apyrimidinic site) lyase 2   [ EC 3.1.-.- ]
Protein also known as:  Apurinic-apyrimidinic endonuclease 2 (AP endonuclease 2).
Gene name:  APEX2
Entry whose protein(s) existence is based on evidence at protein level
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Function as a weak apurinic/apyrimidinic (AP) endodeoxyribonuclease in the DNA base excision repair (BER) pathway of DNA lesions induced by oxidative and alkylating agents. Initiates repair of AP sites in DNA by catalyzing hydrolytic incision of the phosphodiester backbone immediately adjacent to the damage, generating a single-strand break with 5'-deoxyribose phosphate and 3'-hydroxyl ends. Displays also double-stranded DNA 3'-5' exonuclease, 3'-phosphodiesterase activities. Shows robust 3'-5' exonuclease activity on 3'-recessed heteroduplex DNA and is able to remove mismatched nucleotides preferentially. Shows fairly strong 3'-phosphodiesterase activity involved in the removal of 3'-damaged termini formed in DNA by oxidative agents. In the nucleus functions in the PCNA-dependent BER pathway. Required for somatic hypermutation (SHM) and DNA cleavage step of class switch recombination (CSR) of immunoglobulin genes. Required for proper cell cycle progression during proliferation of peripheral lymphocytes.  
  • CuratedUniProtKB
GO molecular function 
DNA bindingdefinition[GO:0003677]  
  • IEAUniProtKB KW
DNA-(apurinic or apyrimidinic site) lyase activitydefinition[GO:0003906] silver  
  • IBARefGenome
Double-stranded DNA 3'-5' exodeoxyribonuclease activitydefinition[GO:0008311] silver  
  • IBARefGenome
Zinc ion bindingdefinition[GO:0008270] silver  
  • IEAInterPro 2 GO
GO biological process 
Base-excision repairdefinition[GO:0006284] silver  
  • IBARefGenome
Cell cycledefinition[GO:0007049]  
  • IEAUniProtKB KW
DNA catabolic process, endonucleolyticdefinition[GO:0000737]  
  • IBARefGenome
  • IEAEC 2 GO
DNA catabolic process, exonucleolyticdefinition[GO:0000738] silver  
  • IBARefGenome
DNA recombinationdefinition[GO:0006310]  
  • IEAUniProtKB KW
Enzymatic activity 
This protein acts as an enzyme. It is known to catalyze the following reaction
EC The C-O-P bond 3' to the apurinic or apyrimidinic site in DNA is broken by a beta-elimination reaction, leaving a 3'-terminal unsaturated sugar and a product with a terminal 5'-phosphate.  
  • CuratedUniProtKB
It requires the following cofactor
Magnesium. Can also utilize manganese. Probably binds two magnesium or manganese ions per subunit (By similarity).  
  • CuratedUniProtKB
It is regulated in the following manner
3'-5' exonuclease activity is activated by sodium and manganese. 3'-5' exonuclease and 3'-phosphodiesterase activities are stimulated in presence of PCNA.  
  • CuratedUniProtKB
According to KEGG, this protein belongs to the following pathway:
Base excision repair  hsa03410+27301  

Biophysicochemical properties

pH Optimum pH is 6.0-8.0.


Biological process 
Cell cycle  definition   [KW-0131]
DNA damage  definition   [KW-0227]
DNA recombination  definition   [KW-0233]
DNA repair  definition   [KW-0234]
Molecular function 
Endonuclease  definition   [KW-0255]
Exonuclease  definition   [KW-0269]
Hydrolase  definition   [KW-0378]
Lyase  definition   [KW-0456]
Nuclease  definition   [KW-0540]
Technical term 
Reference proteome  definition   [KW-1185]

Further external links

GenomeRNAi: 27301