The action of γ -rays on sodium deoxyribonucleate in solution - IV. The mechanism of denaturation

Abstract

The unusually efficient denaturation by γ -rays of sodium deoxyribonucleate ( DNA ) in solution has been examined to confirm that it is effected by the attack of free radicals. A tenfold range of dose produced the same extent of denaturation, provided that the ratio of dose to DNA concentration was kept constant. Free radical inhibitors greatly reduced, and some even eliminated, the denaturing action of radiation, and γ -rays were less effective in the effected by indirect action. The extent of denaturation did not decrease logarithmically with dose and this could be explained by different stabilities in the linkages between the base-pairs of DNA . The mechanism of denaturation is discussed.