title: Antioxidant protein 2 prevents methemoglobin formation in erythrocyte hemolysates.
abstract: Antioxidant protein 2 (AOP2) is a member of a family of thiol-specific antioxidants, recently renamed peroxiredoxins, that evolved as part of an elaborate system to counteract and control detrimental effects of oxygen radicals. AOP2 is found in endothelial cells, erythrocytes, monocytes, T and B cells, but not in granulocytes. AOP2 was found solely in the cytoplasm and was not associated with the nuclear or membrane fractions; neither was it detectable in plasma. Further experiments focused on the function of AOP2 in erythrocytes where it is closely associated with the hemoglobin complex, particularly with the heme. An investigation of the mechanism of this interaction demonstrated that the conserved cysteine-47 in AOP2 seems to play a role in AOP2-heme interactions. Recombinant AOP2 prevented induced as well as noninduced methemoglobin formation in erythrocyte hemolysates, indicating its antioxidant properties. We conclude that AOP2 is part of a sophisticated system developed to protect and support erythrocytes in their many physiological functions.
authors.affiliation: Ludwig Boltzmann Institute for Rheumatology and Balneology, Vienna, Austria. karlms@excite.com
authors.forename: Karl M
authors.initials: KM
authors.lastname: Stuhlmeier
authors.forename: Janet J
authors.initials: JJ
authors.lastname: Kao
authors.forename: Pia
authors.initials: P
authors.lastname: Wallbrandt
authors.forename: Maria
authors.initials: M
authors.lastname: Lindberg
authors.forename: Barbro
authors.initials: B
authors.lastname: Hammarström
authors.forename: Hans
authors.initials: H
authors.lastname: Broell
authors.forename: Beverly
authors.initials: B
authors.lastname: Paigen
mesh_terms: D000818:Animals; D015153:Blotting, Western; D003545:Cysteine / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism; D004912:Erythrocytes / Q000378:metabolism*; D006418:Heme / Q000378:metabolism; D006454:Hemoglobins / Q000378:metabolism; D008706:Methemoglobin / Q000096:biosynthesis / Q000378:metabolism*; D010544:Peroxidases; D054465:Peroxiredoxin VI; D054464:Peroxiredoxins; D011485:Protein Binding / Q000502:physiology; D014176:Protein Biosynthesis; D011506:Proteins / Q000276:immunology / Q000378:metabolism*; D013552:Swine
chemical_list: D006454:Hemoglobins; D011506:Proteins; D006418:Heme; D008706:Methemoglobin; D010544:Peroxidases; D054465:Peroxiredoxin VI; D054464:Peroxiredoxins; D003545:Cysteine