| Abstract: | A radiation-induced transfer of hydrogen from exchangeable to carbon-bound sites occurs in nucleic acids, proteins and their constituents. The G-values for this process are similar within a factor of 2–3 to the G-values for the initial production of stable radicals measured by ESR at room temperature. Unlike the production of radicals, hydrogen transfer in ribonuclease, DNA, and thymine is a linear function of dose in the 0–30 Megarad region. The tritium distributions obtained in proteins by hydrogen transfer are not a measure of the distribution of the “secondary” radicals. From the studies of the effect of temperature, of various scavengers (particularly nitric oxide) and of the dose dependence in the low dose region, it was inferred that for ribonuclease most of the hydrogen transfer takes place during the conversion of the radicals stable at 195°K to the radicals stable at room temperature. The same mechanism also appears to predominate in DNA. |
