SUPEROXIDE-DISMUTASE ACTIVITY IN THE GIANT HEMOGLOBIN OF THE EARTHWORM, LUMBRICUS-TERRESTRIS

The giant hemoglobin, which occurs in free solution in the blood of ea rthworms, contains copper and zinc and exhibits superoxide dismutase a ctivity as assessed by competition assays using cytochrome c or nitrob lue tetrazolium. On a molar basis, the activity of this hemoglobin was approximately 10% that of the mammalian copper, zinc superoxide dismu tase, The dodecamer, which contains the globin chains but lacks the li nker subunits, had very little activity when compared to the complete native molecule, This suggests that the superoxide dismutase activity resides in one of the linker subunits, This is the first report of a s uperoxide dismutase bound to a respiratory pigment. (C) 1996 Academic Press, Inc.