Degradation of deoxyribonucleic acid by a 1,10-phenanthroline-copper complex: the role of hydroxyl radicals.
Degradation of deoxyribonucleic acid (DNA) by 1,10-phenanthroline has been shown to require Cu(II), a reducing agent, and O2. Other metal ions do not substitute for Cu(II), and degradation of DNA is inhibited by metal ions that can form stable complexes with 1,10-phenanthroline, such as Co(II), Cd(II), Ni(II), or Zn(II), as well as by chelators that can bind copper, such as triethyltetraamine, neocuproine, or ethylenediaminetetraacetic acid (EDTA). Neocuproine, a specific copper chelator, is more effective than EDTA in inhibiting the breakdown of DNA. The degradation of DNA shows a requirement for a reducing agent which can be satisfied by either ascorbate or a thiol. A free radical generating system, e.g., xanthine oxidase-hypoxanthine, can substitute for the reducing agent. DNA degradation, in the presence of either an organic reducing agent or xanthine oxidase-hypoxanthine, is inhibited by hydroxyl radical scavengers and by catalase, suggesting that hydroxyl radical is the reactive species in DNA degradation and that hydrogen peroxide is an intermediate in hydroxyl radical generation.
D002374:Catalase; D002614:Chelating Agents; D003300:Copper; D004247:DNA; D005609:Free Radicals; D006900:Hydroxylation; D010084:Oxidation-Reduction; D010618:Phenanthrolines; D013482:Superoxide Dismutase
D002614:Chelating Agents; D005609:Free Radicals; D010618:Phenanthrolines; D003300:Copper; D004247:DNA; D002374:Catalase; D013482:Superoxide Dismutase; C025205:1,10-phenanthroline