Identification of some OH radical-induced products of lysozyme

OH radical reactions with lysozyme in gamma-irradiated N2O saturated aqueous solutions caused formation of allo-threonine, alpha-amino-n-butyric acid, o- and m- tyrosines, and 2- and 3-hydroxytyrosines. These identified radiolytic products were characterized by capillary gas chromatography-mass spectrometry as their trimethylsilyl derivatives after HCl-hydrolysis of irradiated lysozyme. Their initial G-values were also determined using gas chromatography. The possible use of these radiolytic products as monitors of radiation-induced damage to proteins and the sites of attack are also discussed.