Redox activity of the Fe complexes of the chelators assessed by plasmid DNA cleavage assays.

The effects of EDTA, 311m, Triapine, and the most cytotoxic NT analogues (NT and N4mT) on integrity of the plasmid pGEM-7Zf(+) when incubated in the presence of Fe(II) and hydrogen peroxide. Reagents were added in the following order: purified sterile water, chelator (1, 10, and 30 μM), FeSO₄ (10 μM), H₂O₂ (1 mM), and plasmid (10 μg/mL); followed by incubation at room temperature for 30 minutes before loading onto a 1% agarose gel (see “Materials and methods”). Results are a typical experiment from 8 performed.