Radioprotection of Enzyme and Bacterial Systems by Dithiothreitol

The radioprotection of dilute aqueous solutions of the enzyme papain, and of suspensions of Serratia marcescens by the sulfhydryl compound, dithiothreitol, has been demonstrated. The results are considered in terms of the stability of this compound to air oxidation and its free radical reactivity. It has been shown that radical scavenging and radical repair processes are the major causes of the observed radioprotective effect. The effect of medium and of the saturating gas on the radioprotective action of dithiothreitol toward Serratia marcescens is discussed.