The presence of cysteamine was found to prevent the crosslinking of deoxyribonucleic acid (DNA) when irradiated by gamma rays in the form of a nucleoprotein. Electron spin resonance measurements of salmon sperm heads indicated that the protection is brought about by the transfer of a hydrogen atom from the --SH group of the cysteamine to the radicals produced in DNA. In this way the radiation damage in DNA is restored, and radical combination leading to crosslinking is prevented. Oxygen competes with the -SH groups for the radioinduced radicals, and repair by cysteamine is more effective in the absence of oxygen. It is suggested that intracellular -SH compounds are responsible for restitution of radiation damage within cells and that interference with the repair reaction by oxygen is one of the factors responsible for the radiosensitizing action of oxygen. Data on the electron spin resonance spectra at -196 un. Concent 85% C and at room temperature of irradiated nucleoprotein and its constituents DNA and salmine are also presented. (auth)
No takes yet. Share an insight, caveat, or question.
Ormerod et al. (1963) studied this question.
Synapse has enriched 5 related papers. Consider them for comparative context: