Retarding effects of DNA on the autoxidation of liposomal suspensions.

Deoxyribonucleic acid (DNA) is associated with the cell membrane of prokaryotes and the inner nuclear membrane of eukaryotes. The unsaturated fatty acids of phospholipids, which constitute the bilaminar structure of membranes, undergo autoxidation in the presence of O2. Calf thymus DNA was incuabted with methyl archidonate-enriched phosphatidyl choline liposomes in order to study the effect of DNA upon the oxidation of phospholipids while present in their natural in vivo bilayer configuration. DNA retarded the rate of lipid oxidation as monitored by both diene conjugation and the TBA test, but it did not alter the induction period. These results suggest that DNA is scavenging free radicals produced within the phospholipid bilayer.