The effects of cupric ions on the radiolytic inactivation of beef heart lactate dehydrogenase and rabbit muscle enolase were investigated. A significant radiolytic sensitization of lactate dehydrogenase by Cu2+ was observed, but no sensitization of enolase occurred. A decrease of sulfhydryl groups resulted when lactate dehydrogenase was irradiated in the presence of Cu2+ ions. The Cu2+ was a competitive inhibitor, thus indicating binding to the active-site of lactate dehydrogenase. A mechanism involving the binding of Cu2+ to the essential sulfhydryl groups of lactate dehydrogenase and an attack by OH radicals is proposed to account for the radiolytic sensitization observed.

This content is only available as a PDF.
You do not currently have access to this content.