Radiation-Induced Transformations of Tryptophan and Its Derivatives in Oxygenated Ethanol

Abstract

The interaction of tryptophan, tryptamine, and 3-indolepropionic acid with peroxyl radicals formed during the radiolysis of oxygen-saturated ethanol has been studied using steady-state radiolysis. It has been found that 3-indolepropionic acid has a low reactivity toward peroxyl radicals. At the same time, both tryptamine and, to a lesser extent, tryptophan inhibit the radiation-induced processes of ethanol oxidation due to electron transfer from the lone pair of the amino group to oxygen-centered radicals. The tryptophan and tryptamine radical cations formed in these reactions are predominantly regenerated to the parent compounds upon interaction with \({\text{O}}_{2}^{{\bullet - }}\) and \({\text{HO}}_{2}^{\bullet },\) as evidenced by the low radiation-chemical yields of decomposition of the test compounds.