The action of ionizing radiation on DNA in the presence of quinacrine. I. UV absorption and fluorescence measurements.

It is shown by UV absorption and absolute fluorescence spectroscopy of solutions containing both DNA and quinacrine that the components experience mutual radio-protection due to scavenging of water radicals. From measurements at different ionic strengths it is inferred that quinacrine bound to DNA is more efficiently protected than the free compound. Furthermore, release of bound quinacrine from DNA is observed at higher doses.