Radiation damage of proteins in the solid state: changes of amino acid composition in catalase.

Catalase has been irradiated with 100 keV electrons under conditions simulating the hazards of electron microscopic imaging. Amino acid analysis reveals a definite pattern of amino acid destruction which is well correlated with the particular chemical structures of amino acid side chains. This pattern appears to be distinctly different from the sensitivity pattern for monoamino acid systems, which fact is ascribed to intramolecular energy transfer and selective attack of liberated radicals.