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)

When FMN is added to rat liver mitochondria or mitoplasts it is reduced at a rate of approx. 0.2 nmol . min-1 . mg-1 protein. Sonicated mitochondria do not reduce exogenous FMN. The reduction depends on drainage of reducing equivalents from the respiratory chain at the level of ubiquinone. The net production of reduced FMN is detectable only at oxygen concentrations less than 4-5 muM. The mitochondrial ubiquinol-FMN oxidoreductase provides a mechanism for the coupling of FMN-reduction to the reductive mobilization of iron from ferritin. The results are discussed in relation to the role of ferritin as a donor of iron to the mitochondria.
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PMID:Reduction of exogenous FMN by isolated rat liver mitochondria. Significance to the mobilization of iron from ferritin. 723 74

It has been reported that iron overload in beta-thalassemia leads to an enhanced generation of reactive oxygen species and to oxidative stress. We have studied the oxidant/antioxidant imbalance in the blood of 48 transfusion-dependent beta-thalassemic patients (TLP) (17 males, 31 females, 11-22 year), under chelation therapy, and in 40 sex and age matched healthy controls (CTR). Plasma and lymphocyte levels of vitamin E (Vit E), ubiquinol (CoQ10H2), ubiquinone (CoQ10), plasma concentrations of vitamin A (Vit A), beta-carotene, lycopene, vitamin C (Vit C), total thiols, fatty acid patterns of phospholipids (PL-FA), and plasma and urinary markers of lipoperoxidation (TBA-RM, conjugated dienes, and azelaic acid (AZA), as well as the urinary levels of catecholamine and serotonin metabolites, were evaluated by gas chromatography-mass spectrometry (GC-MS), HPLC and spectrophotometry. Routine laboratory blood analyses were performed on the same samples; 39/48 TLP were HCV positive. Blood samples were collected just before transfusion, the 24 h urine samples the day before. Our results clearly showed that a severe oxidative stress occurs in the plasma of TLP in comparison with CTR. In fact, the levels of lipophilic antioxidants and ascorbate were severely depleted: CoQ10H2 (-62.5%), total CoQ10 (-35.1%), Vit E (-43.8%), beta-carotene (-31.1%), lycopene (-63.7%), Vit A (-35.9%), Vit C (-23.1%). The impairment of the antioxidant status was associated with elevated plasma levels of by-products of lipoperoxidation and urinary concentrations of catecholamine metabolites and of AZA, indicating a high degree of both neurological stress and lipoperoxidation. A significant positive correlation was found between vitamin E and non-transferrin-bound iron (NTBI) (r = -0.81; p < 0.001), while no correlation was found between antioxidant depletion and ferritin serum levels, average blood consumption, or the presence of clinical complications. The administration of selective antioxidants along with an appropriate diet might represent a promising way of counteracting oxidative damage and its deleterious effects on the progression of the disease.
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PMID:Blood antioxidant status and urinary levels of catecholamine metabolites in beta-thalassemia. 1040 Apr 57

Chlorella protothecoides cultures grown in a nitrogen-free bleaching medium (BM-N) in the dark rapidly degraded chlorophyll (Chl) to red catabolites. This degreening process was investigated under different growth conditions. Supply of nitrogen to the culture medium (BM+N) inhibited bleaching and the synthesis of catabolites as did the addition to BM-N of cycloheximide or a chelator, 2,2'-bipyridyl. In contrast, chloramphenicol or the protease inhibitor E64 had no effect. During bleaching, Chl breakdown was accompanied by the degradation of cellular proteins such as light-harvesting complex II, cytochrome f and protochlorophyllide oxido-reductase. During growth in BM-N, protease activity increased and proteins immunologically detectable with an antibody against a senescence-enhanced cysteine protease accumulated. cDNAs from BM-N and BM+N cells were used for differential and subtractive screening to isolate cDNAs representing genes with degreening-enhanced expression (dee) in C. protothecoides. Several different dees were identified with different patterns of expression during Chlorella growth but which were all expressed at higher levels during bleaching. Among these, dee4 was most abundant and its expression was exclusive in BM-N cultures. Analysis of the dee sequences showed that they encode different proteins including a novel amino acid carrier (dee4), ferritin, ATP-dependent citrate lyase, a Ca2+-binding protein, MO25, ubiquinone-cytochrome c-reductase and several new proteins.
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PMID:Chlorophyll breakdown in Chlorella protothecoides: characterization of degreening and cloning of degreening-related genes. 1079 14

In prokaryotes and yeast, the general mechanism of biogenesis of iron-sulfur (Fe-S) clusters involves activities of several proteins among which IscS and Nfs1p provide, through cysteine desulfuration, elemental sulfide for Fe-S core formation. Although these proteins have been well characterized, the role of their mammalian homolog in Fe-S cluster biogenesis has never been evaluated. We report here the first functional study that implicates the putative cysteine desulfurase m-Nfs1 in the biogenesis of both mitochondrial and cytosolic mammalian Fe-S proteins. Depletion of m-Nfs1 in cultured fibroblasts through small interfering RNA-based gene silencing significantly inhibited the activities of mitochondrial NADH-ubiquinone oxidoreductase (complex I) and succinate-ubiquinone oxidoreductase (complex II) of the respiratory chain, as well as aconitase of the Krebs cycle, with no alteration in their protein levels. Activity of cytosolic xanthine oxidase, which holds a [2Fe-2S] cluster, was also specifically reduced, and iron-regulatory protein-1 was converted from its [4Fe-4S] aconitase form to its apo- or RNA-binding form. Reduction of Fe-S enzyme activities occurred earlier and more markedly in the cytosol than in mitochondria, suggesting that there is a mechanism that primarily dedicates m-Nfs1 to the biogenesis of mitochondrial Fe-S clusters in order to maintain cell survival. Finally, depletion of m-Nfs1, which conferred on apo-IRP-1 a high affinity for ferritin mRNA, was associated with the down-regulation of the iron storage protein ferritin.
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PMID:RNA silencing of mitochondrial m-Nfs1 reduces Fe-S enzyme activity both in mitochondria and cytosol of mammalian cells. 1678 28