FIG. 3.

Effect of E3330 analogues on APE1 and thioredoxin redox function. Increasing amounts of E3330 or its analogues (RN8-51, RN10-52, and RN7-60) were incubated for 30 min with 2 μl purified human APE1 or thioredoxin (reduced with 1.0 mM DTT, then diluted to 2 μg/μl with 0.2 mM DTT in PBS) in EMSA reaction buffer with total volume of 10 μl. The EMSA assay was performed as described in Methods. E3330 (A–C), RN8-51 (A), and RN10-52 (B) blocked the redox activity of APE1 but not thioredoxin. RN7-60 (C) blocked the redox activity of both, but affected APE1 more than thioredoxin.