Dioxygenase that repairs alkylated nucleic acid bases by direct reversal oxidative dealkylation. Can process both double-stranded (ds) and single-stranded (ss) DNA substrates, with a strong preference for dsDNA (PubMed:16174769, PubMed:16642038, PubMed:18519673). Uses molecular oxygen, 2-oxoglutarate and iron as cofactors to oxidize the alkyl groups that are subsequently released as aldehydes, regenerating the undamaged bases. Probes the base pair stability, locates a weakened base pair and flips the damaged base to accommodate the lesion in its active site for efficient catalysis (PubMed:16174769, PubMed:16642038, PubMed:18519673) (By similarity). Repairs monoalkylated bases, specifically N1-methyladenine and N3-methylcytosine, as well as higher order alkyl adducts such as bases modified with exocyclic bridged adducts known as etheno adducts including 1,N6-ethenoadenine, 3,N4-ethenocytosine and 1,N2-ethenoguanine (By similarity). Acts as a gatekeeper of genomic integrity under alkylation stress. Efficiently repairs alkylated lesions in ribosomal DNA (rDNA). These lesions can cause ss- and dsDNA strand breaks that severely impair rDNA transcription (By similarity). In a response mechanism to DNA damage, associates with PCNA at replication forks to repair alkylated adducts prior to replication (By similarity). 2-oxoglutarate + a methylated nucleobase within DNA + O2 = a nucleobase within DNA + CO2 + formaldehyde + succinate 2-oxoglutarate + an N(1)-methyl-2'-deoxyadenosine in double-stranded DNA + O2 = a 2'-deoxyadenosine in double-stranded DNA + CO2 + formaldehyde + H(+) + succinate 2-oxoglutarate + an N(1)-methyl-2'-deoxyadenosine in single-stranded DNA + O2 = a 2'-deoxyadenosine in single-stranded DNA + CO2 + formaldehyde + H(+) + succinate 2-oxoglutarate + an N(3)-methyl-2'-deoxycytidine in double-stranded DNA + O2 = a 2'-deoxycytidine in double-stranded DNA + CO2 + formaldehyde + H(+) + succinate 2-oxoglutarate + an N(3)-methyl-2'-deoxycytidine in single-stranded DNA + O2 = a 2'-deoxycytidine in single-stranded DNA + CO2 + formaldehyde + H(+) + succinate 2-oxoglutarate + a 1,N(6)-etheno-2'-deoxyadenosine in double-stranded DNA + H2O + O2 = a 2'-deoxyadenosine in double-stranded DNA + CO2 + glyoxal + succinate 2-oxoglutarate + a 1,N(6)-etheno-2'-deoxyadenosine in single-stranded DNA + H2O + O2 = a 2'-deoxyadenosine in single-stranded DNA + CO2 + glyoxal + succinate 2-oxoglutarate + a 3,N(4)-etheno-2'-deoxycytidine in double-stranded DNA + H2O + O2 = a 2'-deoxycytidine in double-stranded DNA + CO2 + glyoxal + succinate 2-oxoglutarate + a 3,N(4)-etheno-2'-deoxycytidine in single-stranded DNA + H2O + O2 = a 2'-deoxycytidine in single-stranded DNA + CO2 + glyoxal + succinate 2-oxoglutarate + a 1,N(2)-etheno-2'-deoxyguanosine in double-stranded DNA + H2O + O2 = a 2'-deoxyguanosine in double-stranded DNA + CO2 + glyoxal + succinate Binds 1 Fe(2+) ion per subunit. Activated by magnesium ions. Interacts with PCNA homotrimer; this interaction is enhanced during the S-phase of the cell cycle. Interacts with nucleolar proteins NCL, UBTF and NPM1. Interacts with XRCC5-XRCC6 heterodimer. Relocates to the replication foci during S-phase. Detected in liver, testis and kidney (at protein level). Detected in heart and testis. The PCNA-binding motif (AlkB homolog 2 PCNA-interacting motif, APIM), mediates the colocalization of ALKBH2 with PCNA at the replication foci, coordinating the repair of alkylated DNA damage with DNA replication. No visible phenotype, and no effect on the level of 1-ethenoadenine in genomic DNA in aging mice. In contrast, the levels of 1-methyladenine in genomic DNA increase over time in aging adults. Belongs to the alkB family.