Radiation damage to DNA in aqueous solution: effects of radiosensitizers.

Systems are described for examining the molecular mode of action of anoxic radiosensitisers with DNA-OH radicals. Pulse radiolysis showed that NPPN reacts with these radicals even in the presence of 0.5 mM oxygen. Analysis of low molecular weight products liberated from DNA by irradiation showed that NPPN does not act in an oxygen-like way but that misonidazole does. Thus a molecular rationale exists for the use of combinations of radiosensitizers.