Hemolysis and iodination of erythrocyte components by a myeloperoxidase mediated system

Abstract

Erythrocytes are hemolyzed by myeloperoxidase, an H2O2 generating system (glucose + glucose oxidase; hypoxanthine + xanthine oxidase) and an oxidizable cofactor (chloride, iodide, thyroxine, triiodothyronine). The combined effect of chloride and either iodide or the thyroid hormones is greater than additive. Myeloperoxidase can be replaced by lactoperoxidase in the iodide, thyroxine and triiodothyronine dependent, but not in the chloride dependent systems. Hemolysis is inhibited by the peroxidase inhibitors, azide and cyanide, and by catalase and is stimulated by superoxide dismutase when the xanthine oxidase system is employed as the source of H2O2. Hemolysis by the iodide dependent system is associated with the iodination of erythrocyte components.