Fig. 2.

Site specificity of DNA damage induced by 2-NO-T in the presence of Cu (II) and NADH. The reaction mixture contained the ³²P-5′-end labeled 211-bp (HindIII*13972–ApaI 14182) DNA fragment, 20 μM/base calf thymus DNA, 0.2 μM or 0.5 μM 2-NO-T, 20 μM CuCl₂, and 100 μM NADH in 10 mM sodium phosphate buffer (pH 7.8) containing 5 μM DTPA. After incubation for 1 h at 37°C, the DNA fragments were treated with piperidine (a) or formamidopyrimidine-DNA glycosylase (Fpg) protein (b) and electrophoresed by the method described in “Materials and methods”. The relative amounts of DNA fragments were measured by scanning the autoradiogram with a laser densitometer