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 ...

BACKGROUND COPD will become the third leading cause of death by 2020. There are many situations in which spirometry, the primary tool for diagnosis of COPD, cannot be performed, and thus, the staging and status of these patients cannot be determined. To date, there is no known biochemical marker used for diagnosing COPD. This study aimed to explore the utility of biomarkers for diagnosis of COP...

Ferroxidase (encoded by the mco gene), a component of a ferrous iron uptake pathway in Pseudomonas aeruginosa, was detected in all of the 35 respiratory clinical isolates surveyed; in contrast, considerable variation in siderophore expression was observed. The ubiquitous expression of this periplasmic ferroxidase suggests that it plays a key role in iron uptake in this opportunistic pathogen.

Ferritin inhibition of myelopoiesis has been associated with intrinsic ferroxidase activity of heavy-chain ferritin and with production of a monokine inhibitor of lipopolysaccharide (LPS)-augmented monocytopoiesis. We report here that intrinsic ferroxidase activity of heavy-chain ferritin is required for stimulated production of the monokine inhibitor of LPS-augmented monocytopoiesis.

It is widely accepted that iron deposition in the iron storage protein ferritin in vitro involves Fe(II) oxidation, and that ferritin facilitates this oxidation at a ferroxidase site on the protein. However, these views have recently been questioned, with the protein ferroxidase activity instead being attributed to autoxidation from the buffer alone. Ligand exchange between another protein with...

Ferritins are 24-mer proteins which store and detoxify intracellular iron. Mammalian ferritins are made of two subunit types, the H- and L-chains, with different functional specificity. The H-chain has a metal-binding site (the ferroxidase center) which confers ferroxidase activity to the protein and accelerates iron incorporation. In the L-chain the center is substituted by a salt bridge. We p...

Release of iron from enterocytes and hepatocytes is thought to require the copper-dependent ferroxidase activity of hephaestin (Hp) and ceruloplasmin (Cp), respectively. In swine, copper deficiency (CD) impairs iron absorption, but whether this occurs in rats is unclear. By feeding a diet deficient in copper, CD was produced, as evidenced by the loss of copper-dependent plasma ferroxidase I act...

A 34 year old diabetic man with a complete deficiency of serum ferroxidase activity, regardless of the presence of serum ceruloplasmin (Cp), a multicopper ferroxidase protein, is described. The patient had had diabetes mellitus for 13 years, and was also found to have retinal degeneration accompanied by the development of a hearing disturbance of unknown aetiology. Laboratory examination showed...

Iron deposition within the iron storage protein ferritin involves a complex series of events consisting of Fe(2+) binding, transport, and oxidation at ferroxidase sites and mineralization of a hydrous ferric oxide core, the storage form of iron. In the present study, we have examined the thermodynamic properties of Fe(2+) binding to recombinant human H-chain apoferritin (HuHF) by isothermal tit...

A sensitivemethod for the detection of ceruloplasmin (ferroxidase) in human serums, using Fe(Il) as the substrate, is described. Initial Fe(ll) concentrations of 30 and 120 p.M may be used, depending on the sensitivity of the spectrophotometer, for the determination of the rate of Fe(Ill) -transferrin formation following the oxidation of Fe(lI) by ceruloplasmin (ferroxidase). Advantages of this...