Comparison of radiation-induced radical yields in short peptides and constituent amino acids by detection of trapped oxygen isotope 18O

This report compares the radiosensitivity of small polypeptides and constituent isolated amino acids using a novel technical approach. The radiation-induced oxygen isotope 18O trapping was measured by means of nuclear reactions. Most of the peptides reveal a higher sensitivity than a mixture of their constituent amino acids. This observation can be rationalized with a simple model which implies intramolecular energy transfer. (author)