Surface plasmon resonance sensorgram for the immobilized recombinant human topoisomerase I (hTopI). (A) A sensorgram of hTopI immobilized on the General Layer Medium sensor surface. (B) Verification of TopI immobilization using serially diluted polyclonal antibodies against TopI. All curves of lower panel were obtained by subtracting the reference signals from the hTopI-free channel (upper panel). (C) Sensorgram of the interaction between immobilized recombinant hTopI and pUC19 plasmid DNA. Concentrations of DNA were 0~1000 ng/mL. Data are representative of three independent experiments.