The ubiquitous 24-meric iron-storage protein ferritin and multicopper oxidases such as ceruloplasmin or hephaestin catalyze oxidation of Fe(II) to Fe(III), using molecular oxygen as oxidant. The ferroxidase activity of these proteins is essential for cellular iron homeostasis. It has been reported that the amyloid precursor protein (APP) also has ferroxidase activity. The activity is assigned t...

The β-amyloid precursor protein (APP), which is a key player in Alzheimer's disease, was recently reported to possess an Fe(II) binding site within its E2 domain which exhibits ferroxidase activity [Duce et al. 2010, Cell 142: 857]. The putative ligands of this site were compared to those in the ferroxidase site of ferritin. The activity was indirectly measured using transferrin, which scavenge...

The aim of this study is to assess the diagnostic level of Ferroxidase activity of ceruloplasmin in tuberculousserosal effusion. The study was carried out on 50 patients suffering from tuberculous pleural and peritoneal effusion and 50 patients suffering from nontuberculous pleural and peritoneal effusion. Mean ± SD of ferroxidase in tuberculous pleural effusion was 1042 ± 112 IU/L and the sens...

In the blood plasma of humans and rats, ceruloplasmin is the major copper-binding protein and ferroxidase, accounting for 70% of the copper present in the plasma, with the rest binding primarily to albumin and a macroglobulin. Systematic studies with fresh plasma were carried out to compare what occurs in the mouse. C57BL6 mice had half as much copper and pPD (p-phenylene diamine) oxidase activ...

strong evidence suggests that the serum ferroxidases (ceruloplasmin andferroxidase II) promote the formation of Fe-III transferrin and thereby stimulate the turnover of iron from tissue stores. Ceruloplasmin is the major ferro.xidase in human serum; whereas, ferroxidase II accotmts for an increased proportion of the activity in less highly developed animals. A large fold increase in total ferro...

The kinetics of the catalysis of Fe(I1) oxidation by crystalline human ferroxidase (ceruloplasmin) has been studied under various conditions at 30’. Two Km values with respect to Fe(U), Km1 = 0.6 /.tM and Km2 = 50 PM, were obtained at pH 6.5, at which ferroxidase gave the maximum activity of 550 Fe(I1) per ferroxidase per min in an acetate buffer. Competition between the two substrates, p-pheny...

BACKGROUND Haptoglobin (Hp) and ceruloplasmin (CP) are 2 plasma antioxidants playing a role in preventing iron-induced oxidative damage. This study presents data related to Hp phenotypes and ceruloplasmin ferroxidase activity in relation to iron store markers in patients with β-thalassemia major. METHODS Blood specimens were collected from 196 subjects (124 β-thalassemia major patients and 72...

A method is described for automated measurement of serum ceruloplasmin ferroxidase activity. In this method, Fe2+ ions are used as the substrate. In addition, a new calibration system without ceruloplasmin is also presented. Optimum assay reaction conditions were determined. Maximal catalytic activity was obtained at 0.45 mol/L acetate buffer, pH 5.8. The reagents and calibrator are stable for ...

Hephaestin (Hp) plays an important role in intestinal iron absorption and is predicted to be a ferroxidase based on significant sequence identity to the serum multicopper ferroxidase ceruloplasmin. Here, we demonstrate that Hp has both amine oxidase and ferroxidase activity in cultured cells and primary intestinal enterocytes with the use of both gel and solution assays. The specificity of the ...

The structure of recombinant Pseudomonas aeruginosa bacterioferritin B (Pa BfrB) has been determined from crystals grown from protein devoid of core mineral iron (as-isolated) and from protein mineralized with approximately 600 iron atoms (mineralized). Structures were also obtained from crystals grown from mineralized BfrB after they had been soaked in an FeSO(4) solution (Fe soak) and in sepa...