Electron spin resonance studies of electron reactions with amino acids in vitreous ices at 77 K

Abstract

The reactions of glycine and alanine with electrons formed during the gamma-radiolysis of frozen alkaline and acidic solutions have been studied by electron spin resonance spectroscopy. In both alkaline and acidic ices, the amino acids react with radiation-induced electrons to give rise to electron adducts which deaminate at higher temperatures to yield the deamination radicals. In acidic ice, the yields of the two species are equal. In alkaline systems, the yield of the deamination radicals in a directly warmed sample is greater than that in a sample warmed after photobleaching. Furthermore, the yield of the deamination radicals is greater than the yield of the corresponding electron adduct. This increase could be due to the reaction of dielectrons formed during irradiation as well as those formed during the photobleaching of trapped electrons as it is known that dielectrons break up into monoelectrons during thermal bleaching.