It has previously been shown that radioinduced organic radicals can be repaired by hydrogen donation from glutathione (GSH) and this repair is in competition with oxygen (damage fixation).

Role of glutathione in affecting the radiosensitivity of molecular and cellular systems

SummaryPulse radiolysis of selenium dioxide in aqueous solution has shown the presence of three selenite radicals in acid–base equilibrium within well defined pH ranges: The selenite radicals react selectively with amino acids, preferentially with the aromatic ones in the order tryptophan > tyrosine > histidine, independently of the acid–base structure of the radical. Kinetic and spectroscopic data on the reaction of selenite radicals with some proteins and parallel inactivation studies generally reflect knowledge on the amino acid residues mainly involved in the radical attack. The investigations at different pH values on the reactivity of selenite radicals with amino acids and proteins and on the transient spectra of the reaction products exhibit different behaviour for the various acid–base structures of the selenite radicals, reflecting the influence of particular ionizable groups in the reacting molecules and the structure modifications at the level of proteins.

Tamba M

Papers

The application of radiation chemistry techniques to enzyme studies.