The Effects of Ionizing Radiations on L-, DL-phenylalanine and L-, DL-tryptophane Studied by Ultra-violet and Infra-red Spectrophotometry

Abstract
Aqueos solutions of L-, DL-phenylalanine and L-, DL-tryptophane were irradiated with 60Co gamma-rays. Marked changes in the u.-v. spectra of the samples and in the infra-red spectra of their solid residues were noted. The radio-sensitivities of these irradiated molecules in terms of G-values have been determined, and the modes of action and the nature of irradiation products are discussed. A common order of radiosensitivities among the three aromatic amino acids in both L-, and DL-forms is observed. Apparent differences in the u.-v. spectral responses of tryptophane on the one hand and phenylalanine and tyrosine on the other are explained. Evidence is presented suggesting some common radiation end-product of a cellulose or sugar type from these aromatic amino acids.