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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ferritin level in serum was investigated in 9 patients with myocardial infarction, all with a history of chest pain of less than 4 hours before admission. A significant rise in serum ferritin level was found in 8 patients. The rise was generally smaller than that seen in acute infection and not significantly correlated to the size of infarction, as estimated from changes in serum levels of myoglobin, ASAT and LDH. The rise started after a mean of 30 hours, the peak being reached within a week (M 4.3 days). Serum ferritin then fell to 120--300% (M 190) of the initial level, where it remained. An initial rise in serum iron levels was unexpectedly seen within 12 hours in 7 patients.
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PMID:Serum ferritin during inflammation. A study on myocardial infarction. 52 35

The detailed reversible binding isotherms of sodium dodecyl sulfate (NaDodSO4) with 13 different initially native proteins are reported; the data were obtained at 20 degrees C and pH 7.1, ionic strength 0.033, with amounts bound with some proteins up to 1.1 g per g of protein. Although the isotherms of some of the proteins do not vary widely, extreme variations between certain classes are found. Thus, for example, hemoglobin and myoglobin both have high affinities and high binding capacities, while gamma-globulin, apoferritin, and transferrin have low initial affinities, and change drastically at higher concentrations. The protein-NaDodSO4 complexes solubilize the water-insoluble dye dimethylaminoazobenzene (DMAB) as effectively as micelles of pure NaDodSO4 when only small amounts (0.2 to 0.5 g/g of NaDodSO4) are bound. In most cases this effectiveness falls progressively as larger amounts are bound, and may even cease altogether at limits characteristic of the individual protein. With some of the latter, a second region of renewed solubilization occurs when substantially higher amounts of NaDodSO4 are present. In all cases, solubilization by ordinary micelles in normal amount occurs when the free NaDodSO4 concentration exceeds the critical micelle concentration, but the binding of NPADodSO4 to the protein also increases, in competition with formation of micelles. With some, but not all proteins the NaDodSO4 bound at concentrations above the cmc also solubilizes DMAB. In such cases the solubilizations by the protein-NaDodSO4 complexes and by the simple micelles are additive. The significance of the differences in binding and solubilizing encountered among these proteins is discussed in terms of surface structure, cooperativity of binding, and protein composition. No certain correlations with content of most amino acids, subunit structure, solubility, and hydrophobicity have been found, but there is a weak inverse dependence of solubilizing effectiveness on molecular size and indications of a strong dependence on content of cationic groups.
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PMID:Differences in the solubilizing effectiveness of the sodium dodecyl sulfate complexes of various proteins. 83 11

Various lactoferrin preparations (iron-saturated and iron-depleted human milk lactoferrins and bovine milk and colostrum lactoferrins) were bound by Aeromonas hydrophila. Binding was (i) reversible (65% of bound lactoferrin was displaced by unlabeled lactoferrin), (ii) specific (lactoferrin but not other iron-containing glycoproteins such as ferritin, transferrin, hemoglobin, and myoglobin inhibited binding), and (iii) significantly reduced by pepsin and neuraminidase treatment of the bacteria. The glycosidic domains of the lactoferrin molecule seem to be involved in binding since precursor monosaccharides of the lactoferrin oligosaccharides (mannose, fucose, and galactose) and glycoproteins which have homologous glycosidic moieties similar to those of the lactoferrin oligosaccharides (asialofetuin or fetuin) strongly inhibited lactoferrin binding. A. hydrophila also binds transferrin, ferritin, cytochrome c, hemin, and Congo red. However, binding of these iron-containing compounds seems to involve bacterial surface components different from those required for lactoferrin binding. Expression of lactoferrin binding by A. hydrophila was influenced by culture conditions. In addition, there was an inverse relationship between lactoferrin binding and siderophore production by the bacterium.
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PMID:Characterization of lactoferrin binding by Aeromonas hydrophila. 131 45

The lactoferrin binding properties of Vibrio cholerae, a non-invasive pathogen were investigated. Screening of fifty V. cholerae strains of different serogroups and serotypes, showed that 10% of the V. cholerae strains bound to 125I-labelled lactoferrin, and 40% of the 125I-labelled lactoferrin bound to V. cholerae strain 623 could be displaced by unlabelled lactoferrin. Other iron-binding glycoproteins and ferroproteins like ferritin, transferrin, haemoglobin, and myoglobin inhibited the binding of 125I-lactoferrin to a lesser degree. Monosaccharides (GalNac, Man, Gal, and Fuc), and other glycoproteins such as fetuin and orosomucoid also inhibited the binding to a lesser extent. V. cholerae 623 showed a cell surface associated-proteolytic activity which cleaved off the cell-bound 125I-labelled lactoferrin. The generation of cryptotopes on the V. cholerae cell surface by proteolytic digestion favoured the binding of ferritin, transferrin, haemoglobin, and haemin, as well as Congo red, to cells of V. cholerae 623.
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PMID:Lactoferrin binding properties of Vibrio cholerae. 150 95

Heme proteins such as myoglobin or hemoglobin, when released into the extracellular space, can instigate tissue toxicity. Myoglobin is directly implicated in the pathogenesis of renal failure in rhabdomyolysis. In the glycerol model of this syndrome, we demonstrate that the kidney responds to such inordinate amounts of heme proteins by inducing the heme-degradative enzyme, heme oxygenase, as well as increasing the synthesis of ferritin, the major cellular repository for iron. Prior recruitment of this response with a single preinfusion of hemoglobin prevents kidney failure and drastically reduces mortality (from 100% to 14%). Conversely, ablating this response with a competitive inhibitor of heme oxygenase exacerbates kidney dysfunction. We provide the first in vivo evidence that induction of heme oxygenase coupled to ferritin synthesis is a rapid, protective antioxidant response. Our findings suggest a therapeutic strategy for populations at a high risk for rhabdomyolysis.
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PMID:Induction of heme oxygenase is a rapid, protective response in rhabdomyolysis in the rat. 163 13

Egg-yolk phospholipid vesicles (liposomes) containing stearylamine cations or phosphatidylserine anions, were formed and entrapped in agarose gel beads (Sepharose 6B) by a dialysis procedure. On a column of entrapped phospholipid-stearylamine (4:1) (cationic) vesicles, 0.36 mg of ferritin was bound per mumol lipids at 0.05 M ionic strength and pH 7. About 30% of the vesicle surface thus became covered with ferritin. Only 0.04 mg of citraconylated myoglobin was bound per mumol lipids, as myoglobin is much smaller than ferritin. Haeme groups were readily inserted into the lipid bilayers. An excess amount of bovine serum albumin (BSA) or ribonuclease A was applied to entrapped ionic vesicles and the bound proteins were eluted by increasing the ionic strength from 0.01 to 0.2 or 0.5 M. After three to five runs, 82-88% of the vesicles (the phospholipids) remained entrapped. The capacity of the cationic vesicle-column for BSA decreased more than did the amount of entrapped vesicles, which indicates a preferential loss of stearylamine. Ion-exchange experiments were done with human plasma and with BSA monomers and dimers on entrapped cationic vesicles. Plasma proteins could be separated. BSA dimers were eluted later than BSA monomers in a sodium chloride gradient and the separation was better than on DEAE-Sepharose. The contact area between the protein and the vesicle surface is important for the binding strength. Protein-vesicle surface interactions can be studied by chromatography on entrapped vesicles.
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PMID:Lipid-vesicle-surface chromatography. 219 93

It is established that wild-type cells of Yersinia pestis absorb exogenous hemin or Congo red and thus grow as pigmented colonies at 26 degrees C on media containing these chromatophores (Pgm+). Pgm+ isolated are known to possess a siderophore-independent mechanism of iron-transport (required for growth in iron-deficient medium) which is absent in avirulent Pgm- mutants. Production of the bacteriocin pesticin and linked invasins (Pst+) is an additional defined virulence factor of yersiniae; mutation of Pgm+,Pst- organisms to pesticin-resistance (Pstr) results in concomitant conversion to Pgm-. In this study, autoradiograms of two-dimensional gels of [35S]methionine-labeled outer membranes from Pgm- mutants were compared to those of the Pgm+,Pst+ or Pgm+,Pst- parent. An apparently single predominant peptide present in these preparations (greater than 10% of total membrane protein) existed as a family of iron-modifiable 17.9-kDa molecules focusing down to isoelectric points of about 4.6 and up to 5.89. Expression of eight detectable Pst(+)-specific peptides was not significantly influenced by exogenous iron. Pgm+ yersiniae constitutively produced pigmentation-specific peptide F and five iron-repressible peptides termed IrpA to IrpE. Typical spontaneous mutation to Pgm- resulted in loss of peptide F and IrpB-E. A rare Pgm+,Pstr mutant, selected on Congo red agar containing pesticin, also lost IrpB-E but retained peptide F. This isolate, like Pgm- mutants, failed to grow in iron-deficient medium. Regardless of phenotype, all yersiniae utilized hemin, hemopexin, myoglobin, hemoglobin, and ferritin, but not transferrin or lactoferrin, as sole sources of iron.
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PMID:Outer membrane peptides of Yersinia pestis mediating siderophore-independent assimilation of iron. 253 80

A surprising unidirectional carrier effect has been observed in the antibody response to myoglobin-ferritin conjugate. This conjugate serves as a hapten-carrier complex for myoglobin-specific T cells to help ferritin-specific B cells make anti-ferritin antibodies, but it does not function for ferritin-specific T cells to help myoglobin-specific B cells to make anti-myoglobin. Therefore, myoglobin-ferritin does not bypass the Ir gene defect of low responders to myoglobin. In contrast, myoglobin-fowl gamma-globulin does induce anti-myoglobin antibodies in low responder mice and thus bypasses the Ir gene defect. Both complexes are covalently coupled. Since the myoglobin-ferritin conjugate serves for myoglobin-specific T cells to help myoglobin-specific B cells, the myoglobin in the conjugate is not altered in a way that would prevent recognition by myoglobin-specific B cells. Similarly, the conjugate serves for ferritin-specific helper T cells to help ferritin-specific B cells, so it can be recognized functionally by ferritin-specific T helper cells. Explanations such as unidirectional induction of or sensitivity to bystander help, or T-cell suppression, have been excluded. While the explanation for this unexpected observation is not yet certain, several possibilities are discussed to explain this novel phenomenon, which is believed to be the first example of such a unidirectional carrier effect between two proteins.
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PMID:A unidirectional carrier effect. 258 3

We have examined the effect of targeting an antigen to the immune system, by covalently coupling it to anti-immunoglobulin (Ig), on its efficacy for T cell stimulation in vitro and its immunogenicity for antibody production in vivo. In vitro, we compared the potency (for stimulation of a ferritin-specific T cell line) of free ferritin, ferritin coupled to goat antimouse IgM (heavy (H) chain specific), ferritin coupled to anti-IgG (H and light (L) chain specific), or ferritin coupled to anti-IgA (H chain specific), as well as a mixture of free ferritin plus goat anti-IgG. The ferritin coupled to anti-IgM or to anti-IgG (H + L), which could bind to surface Ig of B cells, stimulated T cell proliferation at concentrations of ferritin at least 10-fold lower than those required for the other forms of the antigen over the entire time course of the response, with 1000 rad-irradiated spleen cells as presenting cells. Because the goat antibodies were all of the same IgG isotype and coupling ratio, the failure of goat anti-IgA to enhance potency served as a control to exclude Fc receptor binding as the mechanism. The effect was not due to the nonspecific activation of B cells to become more efficient antigen-presenting cells, because mixtures of ferritin plus anti-IgG (H + L) had no effect, and the anti-IgG coupled to ferritin did not enhance presentation of myoglobin to a myoglobin-specific T cell line. The enhanced presentation of ferritin conjugated to goat anti-IgG (H + L) or to anti-IgM was sensitive to radiation doses greater than 2000 R, and was effective at less than one-tenth the number of spleen cells, consistent with the predominance of B cells as antigen-presenting cells for this form of the antigen rather than macrophages and dendritic cells only. When B cells and accessory cells were purified from T-depleted spleen cells, only the B cell preparation but not the accessory cell population manifested enhanced presentation of ferritin coupled to anti-IgG compared with free ferritin, and it was radiosensitive. Finally, allogeneic B cells could not mediate the enhancement in the presence of syngeneic splenic accessory cells (SAC); therefore, the enhancement was not due to shedding of immune complexes from B cells and subsequent presentation by SAC. We conclude that targeting the antigen to B cells as presenting cells greatly enhances its efficacy in vitro.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Enhancement of antigenic potency in vitro and immunogenicity in vivo by coupling the antigen to anti-immunoglobulin. 307 11

The ability of unlabelled heterologous transferrin to interact with transferrin receptors on developing chick myogenic cells was investigated by measuring their capacity to inhibit the surface-binding and internalization of 125I- and 59Fe-labelled ovotransferrin. Transferrins from rat, rabbit, human, and a species of kangaroo (Macropus fuliginosus) were unable to inhibit either surface-binding or internalization of labelled ovotransferrin even at concentrations ten times the molar concentration of the ovotransferrin. Transferrins isolated from the serum of a toad (Bufo marinus) and a lizard (Teliqua rugosa), when added at high concentrations, were found to reduce surface-binding of 125I-Tf by 20-25% but did not inhibit internalization of either 125I-Tf or 59Fe. This suggests that the effects of toad and lizard transferrins are due to non-specific binding to the myogenic cells. In contrast, inhibition of both surface-binding and internalization of labelled ovotransferrin was found when myogenic cells were incubated in the presence of the homologous transferrin (ovotransferrin). The species-specificity of transferrin binding, endocytosis and iron internalization did not vary with the state of proliferation or differentiation of the myogenic cells. However, the intracellular iron utilization was found to differ between differentiating presumptive and terminally differentiated myotubes. Internalized 59Fe was fractioned by gel filtration. In dividing and non-dividing presumptive myoblasts 59Fe was found to elute in three peaks, two with elution volumes corresponding to ferritin and transferrin and one at greater elution volume than that of myoglobin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Species specificity of transferrin binding, endocytosis and iron internalization by cultured chick myogenic cells. 324 19


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