Catalysis of soluble hemoglobin oxidation by free iron on sickle red cell membranes

  • O Shalev
    Department of Medicine-Division of Hematology, University of Minnesota Medical School, Minneapolis 55455, USA.
  • RP Hebbel
    Department of Medicine-Division of Hematology, University of Minnesota Medical School, Minneapolis 55455, USA.

書誌事項

公開日
1996-05-01
DOI
  • 10.1182/blood.v87.9.3948.bloodjournal8793948
公開者
American Society of Hematology

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説明

<jats:p>Abnormal deposition of hemichrome on the inner aspect of the sickle red cell membrane promotes premature cell demise. The steps proximate to hemichrome formation in these cells are poorly understood. To test the hypothesis that the pathologic deposits of free ferric iron located on the inner aspect of sickle cell membranes would be redox active and promote oxidation of soluble oxyhemoglobin, we incubated native versus iron-stripped sickle or normal ghost membranes with oxyhemoglobin S. We found that sickle membranes exerted an exaggerated effect on methemoglobin formation in solution, an effect completely accounted for by their abnormal content of free iron. This ability of sickle membranes to promote hemoglobin oxidation was not diminished by catalase or by presence of a high-affinity, iron-inactivating chelator that is unable to remove membrane iron. Examination of those membranes likewise revealed that their free iron content promoted deposition of additional heme-protein. These results establish that the potential redox couple formed by membrane-associated ferric iron and cytoplasmic oxyhemoglobin is promotive of hemoglobin oxidation and deposition of hemichrome on the membrane. This predicts that removal of pathologic membrane iron might help prevent the detrimental formation of methemoglobin and hemichrome in vivo, insofar as this is accelerated by transition metal.</jats:p>

収録刊行物

  • Blood

    Blood 87 (9), 3948-3952, 1996-05-01

    American Society of Hematology

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