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)

Our earlier studies showed that rabbit muscle phosphoglucomutase was irreversibly inactivated by exposure to a mixture of vitamin C, FeCl3 and O2. The enzyme lost about 70% of its phosphate (V.V. Desphande and J.G. Joshi, J. Biol. Chem. 260, 754-764, 1985). The present report shows that several other iron proteins can substitute for FeCl3 to a varying degree. The rate of inactivation by FeCl3 greater than ferritin greater than hemoglobin = hemerythrin greater than transferrin = ferridoxin = vitamin C. These iron compounds also produced dephosphoenzyme but did not dephosphorylate ATP, ADP, AMP or phospholipids.
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PMID:Differential loss of enzyme activity by vitC and iron containing proteins. 295 84

The present studies were designed to investigate the interaction of Fe3+transferrin-CO3(2-) with the transferrin receptors of the resealed reticulocyte ghost and to assess the degree to which the iron release reaction can be reconstituted in resealed ghosts supplemented with entrapped cytoplasmic components. Reticulocyte, but not erythrocyte, ghosts displayed an intact Fe3+transferrin-CO3(2-) binding capability. When ATP, NADH and ferritin were included during the resealing process, some iron release to the ghosts was observed.
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PMID:The interaction of resealed reticulocyte ghosts with Fe3+-transferrin-CO3(2-). 298 88

Polynuclear iron complexes of Fe(III) and phosphate occur in seawater and soils and in cells where the iron core of ferritin, the iron storage protein, contains up to 4500 Fe atoms in a complex with an average composition of (FeO.OH)8FeO.OPO3H2. Although phosphate influences the size of the ferritin core and thus the availability of stored iron, little is known about the nature of the Fe(III)-phosphate interaction. In the present study, Fe-phosphate interactions were analyzed in stable complexes of Fe(III).ATP which, in the polynuclear iron form, had phosphate at interior sites. Such Fe(III).ATP complexes are important not only as models but also because they may play a role in intracellular iron transport and in iron toxicity; the complexes were studied by extended x-ray absorption fine structure, EPR, NMR spectroscopy, and measurement of proton release. Mononuclear iron complexes exhibiting a g' = 4.3 EPR signal were formed at Fe:ATP ratios less than or equal to 1:3, and polynuclear iron complexes (Fe greater than or equal to 250, EPR silent at g' = 4.3) were formed at an Fe:ATP ratio of 4:1. No NMR signals due to ATP were observed when Fe was in excess (Fe:ATP = 4:1). Extended x-ray absorption fine structure analysis of the polynuclear Fe(III).ATP complex was able to distinguish an Fe-P distance at 3.27 A in addition to the octahedral O at 1.95 A and 4-5 Fe atoms at 3.36 A. The Fe-O and Fe-Fe distances are the same as in ferritin, and the Fe-P distance is analogous to that in another metal-ATP complex. An observable Fe-P environment in such a large polynuclear iron cluster as the Fe(III).ATP (4:1) complex indicates that the phosphate is distributed throughout rather than merely on the surface, in contrast to earlier models of chelate-stabilized iron clusters. Complexes of Fe(III) and ATP similar to those described here may form in vivo either as normal components of intracellular iron metabolism or during iron excess where the consequent alteration of free nucleotide triphosphate pools could contribute to the observed toxicity of iron.
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PMID:Fe(III).ATP complexes. Models for ferritin and other polynuclear iron complexes with phosphate. 298 69

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.
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PMID:Peroxidation of liposomes promoted by human polymorphonuclear leucocytes. 301 66

To evaluate the modulatory effects of trace metals on lymphocyte growth and maturation, thymidine uptake (TU), protein, ATP, Fe, Cu, Zn, ferritin, CD3, CD4, CD8 antigens, surface transferrin receptors (TFR) and interleukin 2 receptors (IL2R) were assessed in normal and T cell leukemia human lymphocytes, cultured in media with varying Fe, Cu and Zn concentrations [Me]. In normal lymphocytes in media with optimal [Me], all values increased significantly after PHA stimulation, except for intracellular metal concentration and CD3+, CD4+, CD8+ cells which were unchanged. In media with low or high [Me], all parameters except for CD8+ cells were decreased. In unstimulated ALL lymphocytes grown in media with optimal [Me], TU, protein, ATP, CD4+, Fe, Cu and ferritin were higher and Zn and CD8+ lower than in unstimulated normal cells: they did not change after PHA stimulation, except in media with low [Me], in which they approached the values of stimulated normal lymphocytes. TFR and IL2R for ALL cells were high in all media: IL2R but not TFR increased after PHA stimulation. No relationship between IL2R and TFR was demonstrable in any media. We conclude that the response of normal lymphocytes to stimuli is sensitive to variation in trace metals, whereas this response, absent in ALL lymphocytes, reappears only in media with low [Me] and is independent from TFR.
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PMID:Trace metals, surface receptors and growth of human normal and leukemic lymphocytes. 326 16

Compelling evidence has been accumulated which indicates that myocardial tissue damage occurring during reperfusion after an ischaemic period may partly be due to the formation of oxygen free radicals and subsequent peroxidative processes. It has been well established that the actual toxicity of free radicals is dependent on the presence of free iron in the heart tissue. Based upon the hypothesis of McCord et al., proposing xanthine oxidase mediated formation of superoxide (O2-.) during the conversion of ATP-breakdown product(s) (hypo)xanthine to urate, we studied whether xanthine oxidase was able to mobilize free iron from the intra- and extracellular iron-binding proteins, ferritin and transferrin. It appeared that there was an O2-.-dependent and O2-.-independent mechanism by which xanthine oxidase could mobilize iron from ferritin while no iron mobilization from transferrin was detectable. The capacity of xanthine oxidase to mobilize iron from ferritin by an O2-.-independent mechanism implies that already during the anoxic/ischaemic period, iron may become available in the tissue which, upon the re-entrance of O2, catalyzes the formation of the very reactive OH radicals. The interaction between endothelial cells and cardiocytes in free radical homeostasis is discussed with the emphasis on the tissue localization of xanthine oxidase. The latter is located in endothelial cells implying an interaction between xanthine oxidase-induced endothelial cells initiated lipid peroxidation and the actual overall myocardial tissue damage.
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PMID:Lipid peroxidation and myocardial ischaemic damage: cause or consequence? 331 Oct 8

NADPH- and iron-dependent lipid peroxidation of rat heart and liver microsomes was measured in the presence and absence of adriamycin. Lipid peroxidation was enhanced by adriamycin when incubated in air and was increased as the pO2 was lowered, to a maximum of 3-4 times the aerobic level at a pO2 of approx. 4 mm Hg. Fe-ADP, Fe-ATP and ferritin were able to catalyse adriamycin-dependent peroxidation of microsomes under low pO2. Superoxide dismutase and catalase had minimal effect. These results indicate that adriamycin-dependent lipid peroxidation is favoured by the low O2 concentration that exist in active muscle cells and suggest that ferritin could provide the iron catalyst for the reaction.
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PMID:Adriamycin-dependent peroxidation of rat liver and heart microsomes catalysed by iron chelates and ferritin. Maximum peroxidation at low oxygen partial pressures. 339 66

The subcellular distribution of iron and transferrin has been studied in isolated rat hepatocytes during uptake of transferrin iron. Iron and transferrin are both rapidly transferred from an extracellular to an intracellular compartment in a process which is slowed down when the cells are deprived of ATP and completely blocked when the cells are incubated at 4 degrees C. The transfer of iron occurs at a higher rate than transferrin. The major part of iron is rapidly incorporated into cytosolic ferritin, i.e. after a 15-min incubation at 37 degrees C 60-70% of cell-associated iron is found in the cytosol as ferritin. The rest of the iron is found in mitochondria (5-10%) and, together with transferrin, in light and heavy endosomes. Following incubation at 4 degrees C, both iron and transferrin are confined to the plasma membrane whereas in ATP-depleted cells the majority of iron and transferrin are recovered in heavy endosomes. The results are consistent with receptor-mediated endocytosis as one mechanism for hepatocyte uptake of iron from transferrin but also suggest an alternative route by which transferrin can donate its iron to the cells and rapidly be released to the extracellular environment without undergoing a complete transferrin cycle.
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PMID:Uptake of iron from transferrin by isolated hepatocytes. The effect of cellular energy metabolism on the intracellular distribution of iron and transferrin. 343 5

Basic red cell ferritin (RCF) content reflects the rate of iron uptake by marrow erythroid cells in patients with anaemia due to chronic inflammation which are sometimes also associated with metabolic disorders of the erythrocytes. For 29 patients with active inflammatic states of chronic rheumatoid arthritis (RA) and microcytic (mean corpuscular volume up to 80fl) or normocytic (MCV 80-95fl) anaemia respectively, the mean RCF content, irrespective of plasma ferritin levels, was determined using a recently established ELISA test. Red cell intermediates (ATP, GSH, 2.3 DP.G) were measured using conventional methods. The results revealed decreased RCF levels (2.8 +/- 1.5 ag/RBC) in 12 patients with RA and normal values (8.8 +/- 4.7 ag/RBC) in 17 patients which obviously did not correlate with the degree of the anaemia. The extent and pattern of the intermediates of RBC did not significantly vary from normal values. Thus, ATP, GSH and 2.3 DPT levels of RBC were only slightly increased up to 10%, especially in those patients with higher anaemic degrees. The findings of our study suggest that conventional indices for iron metabolic disorder in anaemic patients with chronic inflammatic disease should include peripheral microcytosis, transferrin saturation, and RCF content but could neglect plasma ferritin concentrations. Concerning the RBC metabolism this study did not disclose any further influences on iron metabolism parameters due to changes of mean cell age in patients with RA. Specific alterations which might hence produce additional functional disturbances of the erythrocytes in the peripheral microcirculation thus leading further to tissue cell damages in RA could be excluded as well.
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PMID:Red cell metabolism and ferritin levels in iron deficiency anaemia. 359 1

Three different procedures were employed to induce contraction of isolated cochlear outer hair cells. When cells were permeabilized and exposed to calcium and ATP both a shortening of cell length (14%) and a decrease in cell diameter (12-16%) was observed indicating a longitudinal and a circumferential contraction. When intact cells were treated with positively charged ferritin a shortening of about 10% was observed together with an increase in cell diameter. Application of solutions containing high potassium concentrations gave similar but more rapid results as compared with positively charged ferritin. The observed responses of inner ear sensory cells together with their morphological and immunohistochemical characteristics further support the idea that the hearing organ acts as a motile system.
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PMID:Motility in auditory sensory cells. 363 Jul 30


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