title: Bactericidal effect of Fe2+, ceruloplasmin, and phosphate.
abstract: Fe2+, when combined with ceruloplasmin or phosphate, was bactericidal to Escherichia coli at pH 5.0, and when Fe2+, ceruloplasmin, and phosphate were combined, a bactericidal effect was observed under conditions, i.e., short incubation period, in which Fe2+ plus ceruloplasmin and Fe2+ plus phosphate were ineffective. Bactericidal activity increased with the ceruloplasmin or phosphate concentration to a maximum and then decreased as their concentration was further increased. Fe2+ was oxidized in the presence of ceruloplasmin, phosphate, or, in particular, a combination of the two. A bactericidal effect was observed when there was only a partial loss of Fe2+, with more extensive oxidation resulting in a loss of bactericidal activity. The bactericidal effect of Fe2+ plus ceruloplasmin and/or phosphate was unaffected by catalase or superoxide dismutase and was not associated with iodination. Fe-EDTA was also bactericidal at an Fe2+: EDTA molar ratio of 1:0.5, where Fe2+ was partially oxidized. However, in contrast to Fe2+ plus ceruloplasmin and/or phosphate, bactericidal activity was inhibited by catalase and was associated with iodination. Combinations of Fe2+ and Fe3+ were not bactericidal under the conditions employed. A requirement for Fe2+ plus either a product of Fe2+ oxidation or an iron ceruloplasmin and/or phosphate chelate for bactericidal activity is proposed.
authors.affiliation: Department of Medicine, University of Washington, Seattle 98195.
authors.forename: S J
authors.initials: SJ
authors.lastname: Klebanoff
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002374:Catalase / Q000378:metabolism; D002413:Cations, Divalent; D002570:Ceruloplasmin / Q000494:pharmacology*; D004492:Edetic Acid / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects*; D005296:Ferrous Compounds / Q000494:pharmacology; D007501:Iron / Q000494:pharmacology*; D007700:Kinetics; D010084:Oxidation-Reduction; D010710:Phosphates / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D002413:Cations, Divalent; D005296:Ferrous Compounds; D010710:Phosphates; C055526:Fe(II)-EDTA; D004492:Edetic Acid; D007501:Iron; D002374:Catalase; D013482:Superoxide Dismutase; D002570:Ceruloplasmin