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:12486230, PubMed:12594517, PubMed:16174769, PubMed:20714506, PubMed:25797601, PubMed:23972994). 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:18432238, PubMed:22659876). 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 (PubMed:12486230, PubMed:12594517, PubMed:16174769, PubMed:20714506, PubMed:25797601, PubMed:23972994, PubMed:26408825). 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 (PubMed:23972994). In a response mechanism to DNA damage, associates with PCNA at replication forks to repair alkylated adducts prior to replication (PubMed:19736315, PubMed:26408825). 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 ascorbate and magnesium ions. Interacts with PCNA homotrimer; this interaction is enhanced during the S-phase of the cell cycle (PubMed:19736315, PubMed:26408825, PubMed:23972994). Interacts with nucleolar proteins NCL, UBTF and NPM1 (PubMed:23972994). Interacts with XRCC5-XRCC6 heterodimer (PubMed:23972994). Relocates to the replication foci during S-phase. Detected in colon, small intestine, ovary, testis, prostate, skeletal muscle, heart, liver and urinary bladder. 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. Belongs to the alkB family.