Radiation-induced changes of structural and functional properties of human hemoglobin. II. Structural and functional characterization of irradiated deoxyhemoglobin.

Gel filtration and SDS-PAGE separation of hemoglobin (Hb) irradiated under argon or N2O show formation of covalent-aggregated Hb molecules. The production of covalent bonds is attributed mainly to the action of hydroxyl radicals, because addition of ethanol, a scavenger of these radicals, suppresses this reaction to a great extent. The oxidized heme iron forming metHb or hemichromes is found in all the separated fractions of irradiated Hb. It is also found that the radiation-modified Hb molecules exhibit a decrease of co-operative binding of oxygen.