Fig. 3
From: Copper-mediated DNA damage caused by purpurin, a natural anthraquinone
Site specificity of purpurin-induced DNA damage in 32P-5′-end-labeled DNA fragments. Reaction mixtures contained the 32P-5′-end-labeled (A) the 337-bp fragment or (B) the 309-bp fragment, 20 μM/base calf thymus DNA, 50 μM purpurin and 20 μM CuCl2 in 200 μl of 10 mM sodium phosphate buffer (pH 7.8) containing 5 μM DTPA. After incubation at 37 °C for 1 h under light shielding, the DNA fragments were treated with piperidine and electrophoresed on a polyacrylamide gel. DNA bases in bold represent preferentially cleaved bases