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

This study demonstrates the ability of aqueous extracts of cigarette smoke to reduce iron and cause its release from ferritin. Superoxide dismutase (SOD) increases the rates of iron release with the less filtered smoke extracts, but has no effect on the rate of iron release caused by aqueous extracts of well-filtered gas-phase cigarette smoke. Faster rates of iron release are observed under anaerobic conditions, and the reducing power of the cigarette smoke extracts is prolonged when incubated in argon. Hydroquinone and catechol, two of the major polyhydroxybenzenes in cigarette smoke, increase in concentration in the smoke extracts as these are subjected to less filtration, and higher concentrations of polyhydroxybenzenes correlate with higher rates of iron release from ferritin. Concomitant with iron release, depletions of amino acids in ferritin are observed. Depletion of histidine is partially prevented by bathophenanthrolinedisulfonate and mannitol, while lysine and arginine depletions remain unaffected. These observations suggest that cigarette smoke components react directly with these amino acid residues in ferritin. Cigarette smoke induced release of iron could alter iron metabolism in the lungs of chronic smokers and contribute to the increase in the total oxidative burden on the lungs of smokers.
 ...
PMID:Release of iron from ferritin by aqueous extracts of cigarette smoke. 158 27

A number of xenobiotics are toxic because they redox cycle and generate free radicals. Interaction with iron, either to produce reactive species such as the hydroxyl radical, or to promote lipid peroxidation, is an important factor in this toxicity. A potential biological source of iron is ferritin. The cytotoxic pyrimidines, dialuric acid, divicine and isouramil, readily release iron from ferritin and promote ferritin-dependent lipid peroxidation. Superoxide dismutase and GSH, which maintain the pyrimidines in their reduced form, enhance both iron release and lipid peroxidation. Microsomes plus NADPH can reduce a number of iron complexes, although not ferritin. Reduction of Adriamycin, paraquat or various quinones to their radicals by the microsomes enhances reduction of the iron complexes, and in some cases, enables iron release from ferritin. Adriamycin stimulates iron-dependent lipid peroxidation of the microsomes. Ferritin can provide the iron, and peroxidation is most pronounced at low pO2. Complexing agents that suppress intracellular iron reduction and lipid peroxidation may protect against the toxicity of Adriamycin.
 ...
PMID:Ferritin, lipid peroxidation and redox-cycling xenobiotics. 164 77

Lipid peroxidation of erythrocyte membrane was caused by phorbol myristate acetate (PMA)-stimulated polymorphonuclear leukocytes (PMN) in the presence of ferritin. PMN themselves were not peroxidized. A lag period was observed before the start of the peroxidation reaction. In contrast, ferritin iron was continuously released by PMA-stimulated PMN, suggesting that accumulation of free iron in the reaction system was important for proceeding of the peroxidation reaction. Superoxide dismutase, catalase, hydroxyl radical scavengers and an iron chelator, diethylenetriaminepenta-acetic acid, inhibited the lipid peroxidation, indicating that the lipid peroxidation is initiated by a hydroxyl radical generated from the interaction of H2O2 with ferrous iron released from ferritin.
 ...
PMID:Lipid peroxidation of the erythrocyte membrane caused by stimulated polymorphonuclear leukocytes in the presence of ferritin. 193 70

NADH-lipoamide dehydrogenase mobilized iron from ferritin under aerobic conditions. Superoxide dismutase strongly inhibited this mobilization, indicating that the superoxide radical is generated by the enzymatic reaction and release iron from ferritin. Addition of lipoamide as an electron acceptor to NADH-lipoamide dehydrogenase increased the release of iron from ferritin and this release was partially inhibited by superoxide dismutase. Similarly, addition of menadione (2-methyl-1, 4-naphthoquinone) as an electron acceptor to xanthine-xanthine oxidase promoted the release of iron from ferritin and this release was strongly inhibited by superoxide dismutase. These results suggest that dihydrolipoamide and semiquinone of menadione can react with oxygen to form the superoxide radical that mediates release of iron from ferritin.
 ...
PMID:Superoxide-mediated release of iron from ferritin by some flavoenzymes. 215 90

Iron was released from ferritin by the catecholamine analog, 6-hydroxydopamine. Iron release was more efficient under nitrogen than in air, suggesting that the hydroquinone has the major role in the process. Superoxide dismutase, alone or in combination with catalase, strongly inhibited 6-hydroxydopamine oxidation and greatly enhanced the amount of ferritin iron release. Catalase alone had a similar, but lesser effect. Iron released from ferritin accelerated the autoxidation of 6-hydroxydopamine. This occurred by a mechanism that was inhibited by a combination of catalase and a chelator, and to a lesser extent by superoxide dismutase. 6-Hydroxydopamine was a good promoter of metal-catalysed lipid peroxidation, and ferritin-iron participated in the process. Superoxide dismutase, and to a lesser extent catalase, stimulated peroxidation catalysed by adventitious levels of iron, but in the presence of ferritin, each enzyme was inhibitory. It appears that the greatly enhanced iron release seen under these conditions accelerated the autoxidation of 6-hydroxydopamine so that less was available to participate in peroxidative reactions. However, when 6-hydroxydopamine autoxidation was prevented by a combination of superoxide dismutase and catalase, lipid peroxidation was also inhibited, suggesting that some intermediate of autoxidation is a further requirement for the process.
 ...
PMID:6-Hydroxydopamine releases iron from ferritin and promotes ferritin-dependent lipid peroxidation. 251 34

The diabetogenic action of alloxan is believed to involve oxygen free radicals and iron. Incubation of glutathione (GSH) and alloxan with rat liver ferritin resulted in release of ferrous iron as assayed by spectrophotometric detection of ferrous-bathophenanthroline complex formation. Neither GSH nor alloxan alone mediated iron release from ferritin. Superoxide dismutase (SOD) and catalase did not affect initial rates of iron release whereas ceruloplasmin was an effective inhibitor of iron release. The reaction of GSH with alloxan resulted in the formation of the alloxan radical which was detected by ESR spectroscopy and by following the increase in absorbance at 310nm. In both instances, the addition of ferritin resulted in diminished alloxan radical detection. Incubation of GSH, alloxan, and ferritin with phospholipid liposomes also resulted in lipid peroxidation. Lipid peroxidation did not occur in the absence of ferritin. The rates of lipid peroxidation were not affected by the addition of SOD or catalase, but were inhibited by ceruloplasmin. These results suggest that the alloxan radical releases iron from ferritin and indicates that ferritin iron may be involved in alloxan-promoted lipid peroxidation.
 ...
PMID:Alloxan- and glutathione-dependent ferritin iron release and lipid peroxidation. 253 98

Alloxan in the presence of reduced glutathione released iron from ferritin which is the major intracellular iron storage protein. Superoxide dismutase inhibited by only about 30% the alloxan-dependent iron release from ferritin but completely inhibited the iron release from ferritin induced by hypoxanthine-xanthine oxidase. Under anaerobic conditions, the ESR spectrum of alloxan radical was obtained and interaction with ferritin resulted in a marked diminution of the alloxan radical signal. These results indicate that alloxan radical rapidly releases iron from ferritin.
 ...
PMID:Iron release from ferritin by alloxan radical. 285 Apr 25

Human polymorphonuclear leucocytes were found to promote peroxidation of phospholipid liposomes upon stimulation by phorbol myristate acetate. Peroxidation required the presence of either pyrophosphate-chelated or ADP-chelated iron, whereas iron chelated to EDTA or ATP had no effect. Peroxidation was also catalyzed by ferritin, but not by transferrin. Superoxide dismutase abolished the peroxidation, whereas catalase and apparently also the hydroxyl radical scavenger dimethyl sulphoxide were inactive, indicating that the peroxidation was mediated by superoxide radicals but not by hydrogen peroxide or hydroxyl radicals. Xanthine oxidase-promoted peroxidation was studied for comparison and showed similar characteristics except that transferrin catalyzed the peroxidation. Peroxidation of membrane lipids may be a mechanism whereby granulocytes cause tissue damage in inflammation. The drugs paracetamol, gentisic acid and 5-aminosalicylic acid inhibited lipid peroxidation, probably through their ability to react with the superoxide anion.
 ...
PMID:Peroxidation of liposomes promoted by human polymorphonuclear leucocytes. 301 66

The reductive release of ferritin iron by several naturally occurring o-diphenols was studied. The initial rate of iron release was quantified by spectrophotometric measurement of the Fe(ferrozine)3(2+) complex, which absorbs maximally at 562 nm. The initial rate of iron release was dependent upon o-diphenol concentration, but not on the concentration of the chromophoric chelating agent, ferrozine, Stoichiometric measurements resulted in a ratio of 2Fe(II) released per molecule of o-diphenol. The series of o-diphenols studied included, caffeic acid, chlorogenic acid, dihydrocaffeic acid, 3,4-dihydroxybenzoic acid, and several analogs. These reductants represent an oxidation reduction potential range of 0.38 volts. A direct correlation between reducing power of the o-diphenols and rate of ferritin iron release was observed. Superoxide dismutase, catalase, mannitol, or general radical traps had no effect on the rate of iron removal; however, EDTA and oxalate inhibited iron release. A mechanism for ferritin iron reduction and release by o-diphenols consistent with the experimental observations is discussed.
 ...
PMID:Reduction and release of ferritin iron by plant phenolics. 313 80

Ferritin iron release, a process of considerable interest in biology and medicine, occurs most readily in the presence of reducing agents. Here is described a kinetic assay for measuring the rate of ferritin iron removal promoted by various reductants. The new procedure uses ferrozine as a chromophoric, high-affinity chelator for the product, Fe(II). The initial rate of iron release is quantified by continuous spectrophotometric measurement of the Fe(ferrozine)2/3+ complex which absorbs maximally at 562 nm. The initial rate of iron mobilization is dependent on reductant concentration, but not on the concentration of the chelating agent, ferrozine. Saturation kinetics are observed for all reductants, including dihydroxyfumarate, cysteine, caffeic acid, ascorbate, and glutathione. Superoxide dismutase greatly inhibits ferritin iron release by ascorbate, but has little or no effect on the reducing action of dihydroxyfumarate, cysteine, caffeic acid, or glutathione. Ferritin iron removal by dihydroxyfumarate was inhibited by various metal ions. This new assay may be used for rapid screening of test compounds for treatment of iron overload and for investigation of the mechanistic aspects of ferritin iron reduction.
 ...
PMID:Reductive release of ferritin iron: a kinetic assay. 321 30


1 2 3 Next >>