OXIDATION REACTIONS OF HUMAN, OPOSSUM (DIDELPHIS-VIRGINIANA) AND SPOT(LEIOSTOMUS-XANTHURUS) HEMOGLOBINS - A SEARCH FOR A CORRELATION WITH SOME STRUCTURAL-FUNCTIONAL PROPERTIES

1. Relative to human HbA, opossum (Didelphis virginiana) hemoglobin wa s found to be more susceptible to autoxidation. While the initial rate of autoxidation of spot (Leiostomus xanthurus) hemoglobin is close to that of HbA, complete oxidation occurs in 50 hr. 2. Direct addition o f hydrogen peroxide (H2O2) induced oxidation of hemoglobins in a defin ite order: spot Hb > HbA > opossum Hb. Excess H2O2 led to heme degrada tion and precipitation that occurred much faster for spot Hb than the case with other proteins. 3. Exposure of hemoglobins to a continuous f lux of H2O2, generated by the glucose/glucose oxidase system, induced the formation of heterogenous protein-associated oxidation products. 4 . Differential reactivity among these hemoglobins under the same or di fferent oxidative conditions, with respect to methemoglobin formation and stability of the ferric form, may reflect the differences in the l ocal heme environment of these proteins.