Ceruloplasmin is a ferroxidase that interacts with ferroportin to export cellular iron, but is not expressed in neurons. We recently reported that the amyloid precursor protein (APP) is the analogous iron-exporting chaperone for neurons and other cells. The ferroxidase activity of APP has since been called into question. Using a triplex Fe2+ oxidation assay, we analyzed the activity of a solubl...

The paper describes a study of Fe(II) oxidation and the formation of Fe(III)-apoferritin complexes in recombinant human H-chain ferritin and its variants. The effects of site-directed changes in the conserved residues associated with a proposed ferroxidase centre have been investigated. A change in any of these residues is shown to reduce the rate of Fe(II) oxidation, confirming the importance ...

The reaction between crystalline human ferroxidase (ferro:On oxido-reductase, EC 1.12.3) and the substrate, Fe(H), was studied by a stop-flow method. The rate constants for four separate steps-enzyme-substrate complex formation, separation of product from the enzyme, reoxidation by molecular oxygen, and a rate-determining step-were estimated to be kl = 1.2 x lo6 M-I set-I, kp = 13 set-*, ka = 5...

The aim of the current study was to evaluate salivary ferroxidase ceruloplasmin activities in celiac patients with different histopathological severity. This study included 75 celiac patients with different mean age (18.68 ± 11.13) year, who had positive screen for celiac antibodies, and who had gastrointestinal symptoms. In order to simplify the comparison with the healthy control group, celia...

1. Copper deficiency was induced in five Friesian cattle offered a semi-synthetic diet containing less than 1 mgCu/kg. Changes in blood and liver Cu contents and in the Cu-containing enzymes, ferroxidase I (caeruloplasmin; EC 1.16.3.1) and monoamine oxidase (EC 1.4.3.4) of plasma and cytochrome oxidase (EC 1.9.3.1) of liver and skeletal muscle were monitored during Cu depletion. 2. Rapid decrea...

Escherichia coli bacterioferritin was serendipitously crystallized in a novel cubic crystal form and its structure could be determined to 2.5 A resolution despite a high degree of merohedral twinning. This is the first report of crystallographic data on 'as-isolated' E. coli bacterioferritin. The ferroxidase active site contains positive difference density consistent with two metal ions that ha...

Hephaestin is a vertebrate multicopper ferroxidase important for the transfer of dietary iron from intestinal cells to the blood. Hephaestin is mutated in the sex-linked anemia mouse, resulting in iron deficiency. However, sex-linked anemia mice still retain some hephaestin ferroxidase activity. They survive, breed, and their anemia improves with age. To gain a better understanding of the role ...

The high affinity iron uptake complex in the yeast plasma membrane (PM) consists of the ferroxidase, Fet3p, and the ferric iron permease, Ftr1p. We used a combination of yeast two-hybrid analysis, confocal fluorescence microscopy, and fluorescence resonance energy transfer (FRET) quantification to delineate the motifs in the two proteins required for assembly and maturation into an uptake-compe...