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)

Response of iron, copper, and zinc status to supplementation with Zn or a combination of Zn and Fe was assessed in adult females in a 10-wk study. Group Z received 50 mg Zn/d as Zn gluconate; group F-Z received 50 mg Fe as ferrous sulfate monohydrate in addition to the Zn. For Group Z, serum ferritin, hematocrit, and erythrocyte Cu,Zn-superoxide dismutase (ESOD) were significantly lower (p less than 0.05) after 10 wk supplementation compared with pretreatment levels. Serum Zn increased (p less than 0.01) but no change occurred in serum ceruloplasmin, hemoglobin, or salivary sediment Zn with treatment. For Group F-Z ESOD decreased with treatment as did salivary sediment Zn (p less than 0.05). Serum ferritin and serum Zn increased significantly, but hemoglobin, hematocrit, and ceruloplasmin were not affected by this treatment. Supplementation with Zn poses a risk to Fe and Cu status. Inclusion of Fe with Zn ameliorates the effect on Fe but not on Cu status.
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PMID:Iron, copper, and zinc status: response to supplementation with zinc or zinc and iron in adult females. 291

Microsomes incubated with NADPH and the cardiotoxic anticancer drug adriamycin reductively release their bound nonheme iron, which is accounted for by ferritin and an as yet uncharacterized nonferritin pool. The reaction is mediated by one-electron reduction of adriamycin to semiquinone radical and subsequent reoxidation of this radical at the expense of membrane iron to regenerate adriamycin and promote Fe2+ release. The semiquinone radical of adriamycin can also reoxidize at the expense of molecular oxygen to form superoxide. However, superoxide dismutase does not inhibit Fe2+ release, indicating either that superoxide is not involved in iron reduction or that superoxide reacts at sites which are sterically inaccessible to the enzyme. It is proposed that the reductive mobilization of membrane-bound iron may mediate the therapeutic or toxic effects of adriamycin, irrespective of the superoxide dismutase content of the target cells.
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PMID:Adriamycin-dependent release of iron from microsomal membranes. 291 83

Five free-living women (ages 28-38 y) and five women (ages 23-44 y) residing in a metabolic unit and eating a constant diet were assessed for variation in indices related to mineral nutrition. Blood was sampled once a month for five months, once a week for five weeks, and once a day for five days to assess analytical and biological variability. Analytical variability was determined by using concurrently run duplicate control samples prepared from plasma or serum pools. Of the measured indices, serum ferritin varied most, with intra-individual variance of 4.72% to 18.0%. Much of this variance may have been because of changes in iron status or in the analytical technique used. Intra-individual month-to-month variance for other indices ranged from 17% for superoxide dismutase (EC 1.15.1.1) to 1.5% for calcium. Correction for long-term analytical variation indicated that most of the variance was associated with the biological component. The higher biological variabilities of some indices, including ferritin or superoxide dismutase, need to be considered when nutritional status is being evaluated or when serial observations are made over a protracted period in clinical studies or trials.
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PMID:Short-term and long-term variability of indices related to nutritional status. I: Ca, Cu, Fe, Mg, and Zn. 292 Apr 3

Ferritin was found to promote the peroxidation of phospholipid liposomes, as evidenced by malondialdehyde formation, when incubated with xanthine oxidase, xanthine, and ADP. Activity was inhibited by superoxide dismutase but markedly stimulated by the addition of catalase. Xanthine oxidase-dependent iron release from ferritin, measured spectrophotometrically using the ferrous iron chelator 2,2'-dipyridyl, was also inhibited by superoxide dismutase, suggesting that superoxide can mediate the reductive release of iron from ferritin. Potassium superoxide in crown ether also promoted superoxide dismutase-inhibitable release of iron from ferritin. Catalase had little effect on the rate of iron release from ferritin; thus hydrogen peroxide appears to inhibit lipid peroxidation by preventing the formation of an initiating species rather than by inhibiting iron release from ferritin. EPR spin trapping with 5,5-dimethyl-1-pyrroline-N-oxide was used to observe free radical production in this system. Addition of ferritin to the xanthine oxidase system resulted in loss of the superoxide spin trap adduct suggesting an interaction between superoxide and ferritin. The resultant spectrum was that of a hydroxyl radical spin trap adduct which was abolished by the addition of catalase. These data suggest that ferritin may function in vivo as a source of iron for promotion of superoxide-dependent lipid peroxidation. Stimulation of lipid peroxidation but inhibition of hydroxyl radical formation by catalase suggests that, in this system, initiation is not via an iron-catalyzed Haber-Weiss reaction.
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PMID:Ferritin and superoxide-dependent lipid peroxidation. 298 54

Microsomes prepared by the usual method of differential centrifugation were found to contain ferritin, superoxide dismutase (SOD), and catalase which could be removed by chromatography on Sepharose CL-2B. Addition of purified rat liver ferritin to chromatographed microsomes resulted in a significant stimulation of NADPH-dependent lipid peroxidation which was inhibited by exogenously added SOD. Iron release from ferritin by these microsomes was also inhibited by SOD. Ferritin did not promote NADPH-dependent microsomal lipid peroxidation when added to microsomes isolated in the usual manner, presumably due to the endogenous SOD present in the microsomes. Accordingly, only very low rates of iron release from ferritin were observed with these microsomes. Paraquat (PQ), which generates superoxide O2-. via redox cycling, greatly stimulated iron release from ferritin and lipid peroxidation in chromatographed microsomes. Paraquat had no effect on iron release from ferritin or lipid peroxidation in microsomes. which were not chromatographed unless they were first treated with CN- to inhibit endogenous SOD. These studies indicate that the majority of microsomal iron is contained within ferritin and that following release by O2-. this iron serves to promote the peroxidation of microsomal lipids.
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PMID:Rat liver microsomal NADPH-dependent release of iron from ferritin and lipid peroxidation. 301 80

NADPH-cytochrome P-450 reductase-catalyzed reduction of paraquat promoted the release of iron from ferritin. Aerobically, iron release was inhibited approximately 60% by superoxide dismutase, whereas xanthine oxidase-dependent iron release was inhibited nearly 100%. This suggests that both superoxide and the paraquat cation radical can catalyze the release of iron from ferritin. Accordingly, under anaerobic conditions, the paraquat radical mediated a very rapid, complete release of iron from ferritin. Similarly, the cation free radicals of the closely related chemicals, diquat and benzyl viologen, also promoted iron release. ESR studies demonstrated that electron transfer from the paraquat cation radical to ferritin accounts for the reductive release of iron. The ferritin structure was not altered by exposure to the paraquat radical and also retained its ability to re-incorporate iron. These studies indicate that release of iron from ferritin may be a common feature contributing to free radical-mediated toxicities.
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PMID:Reductive release of iron from ferritin by cation free radicals of paraquat and other bipyridyls. 302 22

Xanthine oxidase is able to mobilize iron from ferritin. This mobilization can be blocked by 70% by superoxide dismutase, indicating that part of its action is mediated by superoxide (O2-). Uric acid induced the release of ferritin iron at concentrations normally found in serum. The O2(-)-independent mobilization of ferritin iron by xanthine oxidase cannot be attributed to uric acid, because uricase did not influence the O2(-)-independent part and acetaldehyde, a substrate for xanthine oxidase, also revealed an O2(-)-independent part, although no uric acid was produced. Presumably the amount of uric acid produced by xanthine oxidase and xanthine is insufficient to release a measurable amount of iron from ferritin. The liberation of iron from ferritin by xanthine oxidase has important consequences in ischaemia and inflammation. In these circumstances xanthine oxidase, formed from xanthine dehydrogenase, will stimulate the formation of a non-protein-bound iron pool, and the O2(-)-produced by xanthine oxidase, or granulocytes, will be converted by 'free' iron into much more highly toxic oxygen species such as hydroxyl radicals (OH.), exacerbating the tissue damage.
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PMID:Superoxide-dependent and -independent mechanisms of iron mobilization from ferritin by xanthine oxidase. Implications for oxygen-free-radical-induced tissue destruction during ischaemia and inflammation. 302 67

Evidence in alcoholics as well as in experimental models support the role of hepatic lipid peroxidation in the pathogenesis of alcohol-induced liver injury, but the mechanism of this injury is not fully delineated. Previous studies of the metabolism of ethanol by alcohol dehydrogenase revealed iron mobilization from ferritin that was markedly stimulated by superoxide radical generation by xanthine oxidase. Peroxidation of hepatic lipid membranes (assessed as malondialdehyde production) was studied during in vitro alcohol metabolism by alcohol dehydrogenase. Peroxidation was initiated by acetaldehyde-xanthine oxidase, stimulated by ferritin, and inhibited by superoxide dismutase or chelation or iron with desferrioxamine. In conclusion, lipid peroxidation may be initiated during the metabolism of ethanol by alcohol dehydrogenase by an iron-dependent acetaldehyde-xanthine oxidase mechanism.
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PMID:Acetaldehyde-mediated hepatic lipid peroxidation: role of superoxide and ferritin. 303 92

This study aimed to elucidate the way in which larvae of the lamprey Geotria australis counteract the potential problems of the very high concentrations of non-haem iron they contain and thereby avoid the deleterious effects associated with iron overload in other vertebrates. Particular attention has been paid to ascertaining whether increasing concentrations of iron are accompanied by (i) change to a less readily available form of iron and (ii) an increase in the activity of those detoxifying enzymes responsible for minimizing the production of harmful hydroxyl radicals via the Haber-Weiss reaction. The mean concentrations of haemosiderin and ferritin in larval G. australis were each far higher in the nephric fold than in either the liver or intestine, but all these concentrations were much greater than those in rat liver. Since haemosiderin releases iron far more slowly than ferritin, the iron it contains is much less readily available to catalyse the Haber-Weiss reaction. It is thus relevant that (i) non-haem iron in the nephric fold occurred to a greater extent as large dense haemosiderin granules than as ferritin molecules and (ii) the proportion of iron in the form of haemosiderin rose with increasing concentration of total non-haem iron. A strong correlation was also recorded between the activity of superoxide dismutase in the nephric fold and the concentrations of total non-haem iron and its haemosiderin and ferritin components. This demonstrates that enzyme detoxification of O2.- rises with increasing amounts of iron. The exceptional iron concentrations in the nephric fold were not reflected by a greater measured activity of superoxide dismutase than that found in other tissues. However, the nephric fold was shown to contain an augmentation factor which is presumed to enhance the activity of this enzyme in vivo. The activity of catalase and glutathione peroxidase, which catalyse the breakdown of H2O2 to O2 and water, were each significantly correlated with the concentration of ferritin.
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PMID:Exceptional iron concentrations in larval lampreys (Geotria australis) and the activities of superoxide radical detoxifying enzymes. 342 99

A lipid peroxidation system consisting of phospholipid liposomes, paraquat, ADP, and NADPH-cytochrome P450 reductase was constituted using ferritin as the sole source of iron. Lipid peroxidation was completely inhibited by superoxide dismutase, essentially not affected by mannitol, but markedly stimulated by catalase. Similar effects of these scavenging agents were observed in incubations void of ADP. These data suggest that O2-, produced by the redox cycling of paraquat, can release iron from ferritin and thereby promote lipid peroxidation. The effects of catalase and mannitol suggest that the initiation of peroxidation, in either the presence or absence of ADP, is not significantly dependent upon the hydroxyl radical produced via an iron-catalyzed Haber-Weiss reaction.
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PMID:Paraquat and ferritin-dependent lipid peroxidation. 393 39


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