Characterization the effect of Mg2+ in hTDP2-mediated 5'-phosphotyrosyl bond cleavage reaction. (A) Time kinetics experiment was performed using 45 pM TDP2 and 20 nM of the 5-sub substrate for 0-12 mins incubating at 37°C. (B) hTDP2 (9 nM) was reacted with 5-sub (50 nM) at 37°C for 7 min in the absence/presence of EDTA and EGTA. (C) hTDP2 (90 pM) was reacted with a 5-sub substrate (40 nM) at 37°C for 7 min in the presence of different concentrations of DNA. Data represent mean values with standard error derived from three independent experiments.