Electron Spin Resonance Studies of Mechanisms for Chemical Protection from Ionizing Radiation

Abstract

Small concentrations of the sulfur-containing chemical protectors cysteine, cysteamine, AET, glutathione, Na2S2O4-in solid solution in certain proteins alter the electron spin resonance produced by ionizing radiations in the protein. Solutions of only 0.5% by weight of cysteine or Na2S2O4 in zein (or two molecules of solute per protein molecule) produce resonances when gamma-irradiated which are entirely different from that of pure zein when gamma-irradiated. These sulfur protectors may form complexes with the proteins they protect and thus absorb the ionization damage that would occur in the "unprotected" protein. Results indicate that an electron hole or electron spin density can migrate through certain segments of polypeptide chains of proteins.