The production of strand breaks in DNA in the presence of the hydroxylamine of SR-2508 (1-[N-(2-hydroxyethyl)acetamido]-2-nitroimidazole) at neutral pH.
The protonated hydroxylamine of SR 2508 has been prepared by radiochemical reduction and then lyophilized, isolated as the hydrochloride salt, and characterized by proton magnetic resonance spectroscopy. Single strand breaks are produced in the plasmid pBR322 when aliquots of a neutralized solution of the hydroxylamine (10-20 mM) are added to air-equilibrated solutions of the plasmid immediately after adjusting the pH. No breaks are observed, if times greater than five min elapse before adding the neutralized hydroxylamine to DNA, or if oxygen is excluded from the reaction mixture. These results suggest that single strand breaks occur because of the existence of a short-lived reactive species, which is produced after pH adjustment. Observations that oxygen is consumed during the pH jump, H2O2 produced and catalase, desferal and radical scavengers inhibit the reaction are consistent with the hydroxyl radical as the active agent.
D004269:DNA, Bacterial; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000494:pharmacology*; D010957:Plasmids; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*
D004269:DNA, Bacterial; D007093:Imidazoles; D011838:Radiation-Sensitizing Agents; C049945:1-(N-(2-hydroxyethyl)acetamido)-2-hydroxylaminoimidazole