(a) Purified MBP-ALKBH1293 analyzed by SDS-PAGE, with purified ALKBH1Ec used as a control. (b) The m6A demethylase activities of ALKBH1Ec, MBP-ALKBH1293, and ALKBH1293 determined by incubating with m6A-containing oligonucleotide, annealing to the complementary oligonucleotide, digesting with DpnII, and analyzing by PAGE and a fluorescence scanner. (c) The AP lyase activity of ALKBH1Ec, MBP-ALKBH1293, and ALKBH1293 determined by incubating with a 3′-fluorescently-labeled oligonucleotide and analyzing as in panel b. (d) Adduct formation associated with AP lyase activity of ALKBH1Ec and MBP-ALKBH1293 examined using a 5′-fluorescently-labeled oligonucleotide and analyzed as for panel b.