title: Increased sensitivity of isolated alpha subunits of normal human hemoglobin to oxidative damage and crosslinkage with spectrin.
abstract: After peroxidation, alpha and beta subunits of normal human hemoglobin demonstrated a significant differential reactivity in their ability to form methemoglobin subunits and irreducible crosslinkages with spectrin. The alpha subunits formed crosslinks with spectrin in the absence of exogenous hydrogen peroxide, whereas both the beta subunit and the intact hemoglobin molecule required a minimum of 40 and 4 microM peroxide, respectively, in order to form these crosslinks. Changes in the amount of methemoglobin occurred at much higher concentrations of hydrogen peroxide for the beta hemoglobin subunit (100 microM H2O2) than for the alpha subunit (0.1 microM H2O2). A possible explanation for the existing reactivity between each of the two hemoglobin subunits and spectrin is considered and discussed. In our notation, alpha subunit = alpha SH and the beta subunit = beta SH.
mesh_terms: D003432:Cross-Linking Reagents; D004591:Electrophoresis, Polyacrylamide Gel; D006454:Hemoglobins / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology; D008565:Membrane Proteins / Q000502:physiology*; D008706:Methemoglobin / Q000138:chemical synthesis; D013049:Spectrin / Q000502:physiology*
chemical_list: D003432:Cross-Linking Reagents; D006454:Hemoglobins; D008565:Membrane Proteins; D013049:Spectrin; D008706:Methemoglobin; D006861:Hydrogen Peroxide