Gamma irradiation of polypeptides: transformation of amino acids.

The formation of aspartic acid from glutamic acid, of aspartic and glutamic acids from proline, of alpha-amino-n-butyric acid from methionine, of aspartic acid from histidine, of dihydroxyphenylalanine from tyrosine, of tyrosine and dihydroxyphenylalanine from phenylalanine, of alanine from cysteine, and of glycine from alanine was observed when aqueous solutions of these amino acids in the form of peptides or polyamino acids were irradiated. When poly-L-glutamic acid or poly-L-proline was irradiated in the presence of C(14)-labeled NaHCO(3), the radioactive carbon was fixed by the aspartic and the glutamic acid.