Reactivity of aliphatic peptides toward hydroxyl radicals in aqueous solution.

増 田高廣,吉 原清隆,篠 原広行,近 藤正春:東 京都立大学理学部化学教室,東 京都世 田谷 区深 沢2-1-1〒158 Rate constants for the hydrogen abstraction reactions of hydroxyl radicals from aliphatic peptides and N-acetyl amino acids were determined by the p-nitrosodimethylaniline method in gamma-irradiated solutions. For peptides, enhancement of reactivity toward hydroxyl radicals was expected, because of disappearance of suppression by NH3+ group. The expectation was confirmed by the obtained rate constants. In order to estimate the partial rate constants for peptides, partial rate constants for the hydrogen abstraction reactions from amino acids were corrected by the factors calculated on the basis of effect of peptide bond formation. The rate constants of peptides and N-acetyl amino acids calculated from the corrected partial rate constants were in good agreement with the experimentally obtained ones.