Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During inflammation, the superoxide anion (O-2) and hydrogen peroxide (H2O2) are produced by stimulated polymorphonuclear leukocytes and macrophages. The toxic effects of these reactive oxygen intermediates increase when traces of iron are present, because iron catalyzes the formation of the hydroxyl radical (OH.). Partially saturated iron-binding proteins, such as transferrin and ferritin, are unable to catalyze OH. formation in vitro. Mobilization of iron from these proteins is necessary for iron stimulation of OH. formation. This paper reports that stimulated polymorphonuclear leukocytes mobilize iron from human and horse ferritin, but not from human transferrin. Iron release from ferritin depends on O-2 because it can be prevented by the addition of superoxide dismutase. Catalase and dimethylsulfoxide have no inhibitory effect on iron mobilization. The efficiency of the iron release increases at low levels of O-2 production. Only O-2 produced by granulocytes is sufficient for iron mobilization, because solid potassium superoxide is also able to release iron from ferritin. We propose that this reaction may potentiate the formation of the OH. radical in inflammatory states.
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PMID:Iron mobilization from ferritin by superoxide derived from stimulated polymorphonuclear leukocytes. Possible mechanism in inflammation diseases. 632 64

Oxygen free radicals are probably involved in the pathogenesis of rheumatoid arthritis (RA). The enzymes involved in protection against oxygen free radicals and H2O2 (superoxide dismutase, catalase, and glutathione peroxidase) were measured. Superoxide dismutase was not increased, glutathione peroxidase was slightly and catalase was strongly elevated in RA synovial fluid (SF) compared with control SF. Although these enzymes are present in SF, the activities are insufficient to protect against oxygen free radicals and H2O2. In contrast to transferrin, ferritin was increased in RA synovial fluid. Ceruloplasmin was also elevated. When rat liver microsomes were used as a target for oxygen free radicals, serum and SF were both protective. Gel filtration experiments showed that the fraction pattern in which there was maximal protective potential against lipid peroxidation corresponded closely to the level of ceruloplasmin. After removal of ceruloplasmin from serum or SF, about 70% of the protective capacity disappeared. It is concluded that ceruloplasmin is an important protector against oxygen free radicals.
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PMID:Protective factors against oxygen free radicals and hydrogen peroxide in rheumatoid arthritis synovial fluid. 674 61

Trypanosoma brucei EATRO 110 infection in deer mice (Peromyscus maniculatus) produced anemia in 15 of 42 mice between postinoculation days 14 and 70. The infected anemic (IA) mice had significantly higher reticulocyte counts (P less than 0.025), spleen (P less than 0.001) and liver (P less than 0.005) weights, and higher parasitemia than did infected nonanemic (INA) mice. gamma-Globulin concentrations of infected mice were markedly increased, and values for INA mice were 10% higher than values for IA mice. Erythrocyte hexokinase, glucose-6-phosphate dehydrogenase, glutathione peroxidase, glutathione reductase, and pyruvate kinase activities were increased in infected mice, whereas phosphofructokinase was only slightly decreased in infected mice. Seemingly, development of anemia was not related to defects in erythrocyte metabolism. Serum iron values of infected mice were similar to those of controls. Storage iron (hemosiderin and ferritin) concentrations were increased in the spleen and to a lesser extent in the liver. The activity of superoxide dismutase, an enzyme that favors conversion of easily mobilized soluble ferritin to poorly mobilized insoluble hemosiderin, was decreased per unit weight of the enlarged spleen, although total activity was increased. The superoxide dismutase activity per unit weight of liver was not altered in infected mice although total liver activities were increased. These findings, as well as the marked reticulocytosis, indicate that lack of iron supply does not have a part in precipitating the anemia of T brucei infection. Leukocytosis was present in infected animals and was associated with lymphocytosis, eosinopenia, basophilia, and monocytosis; these changes were more marked in IA than in INA mice.
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PMID:Pathogenesis of Trypanosoma brucei infection in deer mice (Peromyscus maniculatus): hematologic, erythrocyte biochemical, and iron metabolic aspects. 686 60

Among various human tissues liver had the highest content of both CuZn superoxide dismutase and Mn superoxide dismutase. There were comparatively small differences in CuZn superoxide dismutase among other organs. The Mn superoxide dismutase contents were roughly half as large as the CuZn superoxide dismutase contents. The total amount of CuZn superoxide dismutase in the body was estimated to be 3900 mg. The superoxide dismutase activities of serum and cerebrospinal fluid corresponded to between 0.2-0.3 mg CuZn superoxide dismutase per liter. CuZn superoxide dismutase was apparently the source of the superoxide dismutase activity in cerebrospinal fluid, whereas this enzyme only accounted for about 15% of the serum activity. The superoxide dismutase activities of ceruloplasmin, transferrin and ferritin were very low, 40 000, 350 000 and 330 000 times lower than that of human CuZn superoxide dismutase. These factors contributed very little to serum superoxide dismutase activity. The activity of lymph was more than twice that of serum. Sera from patients with severely impaired renal function or bilaterally nephrectomized had a very high superoxide dismutase activity.
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PMID:Distribution of CuZn superoxide dismutase and Mn superoxide dismutase in human tissues and extracellular fluids. 693 5

Ferritin from horse spleen was found to cause severe chromosome aberrations in cultured Chinese hamster ovary cells. Ferritin at 15 to 170 microgram/ml was clastogenic and at higher doses was cytotoxic. At comparable concentrations of protein or iron, neither apoferritin nor complexed iron was clastogenic. Sulfhydryl compounds glutathione and cysteine reduced the cytotoxic and clastogenic activities of ferritin. Physiological concentrations of glutathione may normally be sufficient to protect cells from damage. The reducing agent ascorbate had little protective effect. Chelating agents varied in their inhibitory activity: ethylenediaminetetraacetic acid (hexadentate) greater than nitrilotriacetic acid (tetradentate) greater than salicylate (bidentate). 2,2'-Bipyridyl enhance the chromosome-damaging action of ferritin while histidine did not markedly alter the frequencies of aberrations. Catalase and superoxide dismutase showed no inhibitory activity. The mechanism of DNA damage may involve reduction of Fe(III) in the ferritin core to Fe(II), followed by reoxidation of Fe(II) with possible formation of free radicals.
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PMID:Chromosome-damaging activity of ferritin and its relation to chelation and reduction of iron. 719 42

Release of iron from ferritin in the presence of polyhydroxy metabolites of benzene i.e., hydroquinone (HQ) or 1,2,4-benzenetriol (BT) was studied in acetate buffer, pH 5.6. The release of iron from ferritin was quantitated by monitoring the formation of iron-ferrozine complex. The presence of hydroquinone (330 microM) did not result in the release of iron from ferritin, whereas the same concentration of BT resulted in the release of significant amounts of iron (3.2 microM/min) from ferritin. BT concentration-dependent increase in iron release from ferritin was observed although the increase was not linear with the concentration of BT. Under a N2 atmosphere the presence of BT resulted in the release of iron (2.1 microM/min) from ferritin. The presence of oxyradical scavengers i.e., albumin, catalase or superoxide dismutase significantly inhibited iron release from ferritin by BT. The iron released from ferritin by BT enhanced lipid peroxidation in rat brain homogenate and released aldehydic products from bleomycin-dependent degradation of DNA. Addition of BT to bone marrow lysate resulted in an increase of iron release as a function of time. These studies indicate that BT is a potent reductant of ferric iron of ferritin and also mobilizes and releases iron from ferritin core. The release of iron from bone marrow lysate by BT may be of toxicological significance as this could lead to disruption of intracellular iron homeostasis in bone marrow cells.
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PMID:Release of iron from ferritin by 1,2,4-benzenetriol. 753 77

Ferritin contains the greatest part of the iron found in the brain, and the release of iron stores from ferritin has an essential role in iron-dependent lipid peroxidation. We examined the effect of cultured microglia on iron mobilization from ferritin. Microglia stimulated by phorbol myristate acetate caused the release of iron from ferritin, which was detected by monitoring iron-ferrozine complex formation. This iron mobilization was mediated by microglial superoxide production, as evidenced by the significant inhibitory effect of superoxide dismutase. The role of superoxide was also supported by the close correspondence of cumulative microglial superoxide production, as demonstrated by the MCLA (Cypridina luciferin analogue)-dependent chemiluminescence assay, to the time course of iron release from ferritin. Iron release induced by activated microglia may be partly responsible for the oxidative damage that is thought to occur in Parkinson's disease and other neurodegenerative disorders.
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PMID:Activated microglia cause superoxide-mediated release of iron from ferritin. 762 46

Cystic fibrosis patients are at risk for nutrient deficiencies from malabsorption related to exocrine pancreatic insufficiency. This research examined the copper homeostasis of children with cystic fibrosis. Our objective was to measure cytochrome oxidase and copper-zinc superoxide dismutase activities in mononuclear cells, neutrophils, and erythrocytes of adolescents with cystic fibrosis, as well as plasma copper and ceruloplasmin. Thirteen adolescents with pancreatic insufficiency caused by cystic fibrosis were compared with 10 age- and sex-matched control subjects. Serum copper concentrations and ceruloplasmin measurements were not significantly different between the two groups. Cytochrome oxidase activity was significantly lower in the mononuclear cells and copper-zinc superoxide dismutase activity was significantly lower in the neutrophils and erythrocytes of the cystic fibrosis group. Other measures of trace element status such as hemoglobin concentration, serum ferritin, serum zinc, glutathione peroxidase activity, and manganese superoxide dismutase activity were not different between the two groups. Reductions in the activity of two copper-dependent enzymes suggest abnormal copper homeostasis in this population.
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PMID:Reduced copper enzyme activities in blood cells of children with cystic fibrosis. 766 Nov 26

The Escherichia coli Fur protein, with its iron(II) cofactor, represses iron assimilation and manganese superoxide dismutase (MnSOD) genes, thus coupling iron metabolism to protection against oxygen toxicity. Iron assimilation is triggered by iron starvation in wild-type cells and is constitutive in fur mutants. We show that iron metabolism deregulation in fur mutants produces an iron overload, leading to oxidative stress and DNA damage including lethal and mutagenic lesions. fur recA mutants were not viable under aerobic conditions and died after a shift from anaerobiosis to aerobiosis. Reduction of the intracellular iron concentration by an iron chelator (ferrozine), by inhibition of ferric iron transport (tonB mutants), or by overexpression of the iron storage ferritin H-like (FTN) protein eliminated oxygen sensitivity. Hydroxyl radical scavengers dimethyl sulfoxide and thiourea also provided protection. Functional recombinational repair was necessary for protection, but SOS induction was not involved. Oxygen-dependent spontaneous mutagenesis was significantly increased in fur mutants. Similarly, SOD deficiency rendered sodA sodB recA mutants nonviable under aerobic conditions. Lethality was suppressed by tonB mutations but not by iron chelation or overexpression of FTN. Thus, superoxide-mediated iron reduction was responsible for oxygen sensitivity. Furthermore, overexpression of SOD partially protected fur recA mutants. We propose that a transient iron overload, which could potentially generate oxidative stress, occurs in wild-type cells on return to normal growth conditions following iron starvation, with the coupling between iron and MnSOD regulation helping the cells cope.
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PMID:Lethal oxidative damage and mutagenesis are generated by iron in delta fur mutants of Escherichia coli: protective role of superoxide dismutase. 773 Feb 58

Chromium(VI) reduction was studied in a system composed of reduced nicotinamide adenine dinucleotide phosphate-cytochrome P450 oxidoreductase (NADPH-P450 reductase) and different iron chelators and iron sources. In an aerobic phosphate buffer containing iron(II), chromium(VI) was not reduced by the Fe2+ probably because of spontaneous autoxidation of Fe2+, but freshly made Fe2+, added directly to a CrVI-containing buffer, reduced CrVI. Under anaerobic conditions, iron(II) reduced chromium(VI) stoichiometrically. A systemic containing ethylenediaminetetraacetic acid (EDTA)-Fe3+, NADPH-P450 reductase and NADPH effectively reduced chromium(VI) anaerobically. Under aerobic conditions this reaction was inhibited by about 45%. Adenosine diphosphate (ADP)-Fe3+, which is a poor acceptor of electrons from NADPH-P450 reductase, reduced chromium(VI) only marginally, Mannitol slightly increased the aerobic CrVI reduction. Addition of superoxide dismutase and catalase, which both regenerate some O2, led to inhibition of CrVI reduction. Ferritin, NADPH-P450 reductase and the iron chelators, EDTA and citrate, reduced CrVI, indicating mobilization of Fe2+ from ferritin. Low levels of EDTA (55 mumol l-1) and citrate (100 mumol l-1) in contrast to high levels (5 mmol l-1) did not increase CrVI reduction in microsomes. Using 4-(2-hydroxyethyl)-1-piperazineethane sulfonic acid buffer instead of phosphate buffer, the CrVI-reducing activity was increased.
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PMID:The role of iron chelators and oxygen in the reduced nicotinamide adenine dinucleotide phosphate-cytochrome P450 oxidoreductase-dependent chromium(VI) reduction. 774 Dec 58


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