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)

The thermal inactivation of horse spleen ferritin was studied over a range of temperatures (36-52 degrees C) in 0.1 M acetate buffer (pH 4.2) as a decrease of its peroxidase activity during tetramethylbenzidine (TMB) oxidation by hydrogen peroxide. The activation energy of this process was 163.3 kJ/mole. Thermodynamic activation parameters for the loss of peroxidase activity of ferritin were calculated. The influence of various detergents on ferritin-dependent oxidation of TMB, ortho-tolidine, and ortho-phenylenediamine (PDA) by hydrogen peroxide was studied in 0.1 M phosphate buffer (pH 6.0) at 20 degrees C. Relatively high concentrations of charged detergents (SDS and cetyltrimethylammonium bromide) decreased the peroxidase activity of ferritin with all three amines, whereas moderate concentrations of the nonionic detergent Triton X-100 did not influence oxidation of these substrates. Increase of dimethylformamide concentration in 0.02 M acetate buffer (pH 4.2) from 5 to 40% strongly decreased the rate of TMB and PDA oxidation by hydrogen peroxide or cumene hydroperoxide. Decrease in the activity of thermally inactivated ferritin with TMB as substrate, reduction of alpha-helical content of the protein at 40-50 degrees C, an inactivating effect of charged surfactants and organic co-solvent on the peroxidase activity of ferritin indicate a very important role of the apoprotein in peroxidase function. A possible mechanism of apoferritin participation in peroxidase catalysis is discussed.
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PMID:Role of the apoprotein in the catalytic peroxidase-like function of ferritin. 948 74

Eight patients undergoing acetate-free biofiltration (AFB) suffered aluminum intoxication. The source of this outbreak was parenteral exposition to high concentrations of aluminum in sodium bicarbonate solutions. The manufacturer of bicarbonate solutions used in AFB was substituted in May 1994 and the solutions were stored in glass containers. At the peak of intoxication (July 1994) serum aluminum determination revealed an average value of 147.3 +/- 21 microg/l. Aluminum levels in bicarbonate solutions were 400 microg/l. Serum ferritin rose from 307.4 +/- 161 to 735.6 +/- 206 ng/ml, whereas MCV decreased significantly from 98.4 +/- 9 to 90.1 +/- 10 fl. No significant changes were found in hemoglobin, neither in plasma iron, nor in iron transferrin saturation. The doses of recombinant human erythropoietin showed a considerable increase. The replacement solutions were changed and a new solution, stored in plastic containers and with aluminum levels lower than 10 microg/l, was used. The biochemical parameters were normalized. This outbreak demonstrates the need for a stringent control of aluminum-containing replacement fluids.
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PMID:Accidental aluminum intoxication in patients undergoing acetate-free biofiltration. 954 86

Ferritin contains most of the iron found in the brain, and the release of iron from ferritin has an essential role in iron-dependent lipid peroxidation. We examined the effect of cultured microglia on the ferritin-dependent lipid peroxidation of phospholipid liposomes monitored by the formation of thiobarbituric acid-reactive substances. Microglia stimulated by phorbol myristate acetate caused lipid peroxidation in the presence of ferritin. This lipid peroxidation was mediated by superoxide produced by the microglia and iron released from the ferritin. Lipid peroxidation 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 iron-dependent lipid peroxidation in the presence of ferritin. 967 69

Using oxidation of o-phenylenediamine (PDA) and tetramethylbenzidine (TMB) by hydrogen peroxide, cumene peroxide (CHP), tert-butyl hydroperoxide (TBHP), and Triton X-45 hydroperoxide (Triton X-45-HP), the peroxidase activity of horse spleen ferritin was investigated in reversed micelles of aerosol OT (AOT) in heptane with various hydration degrees. With hydrogen peroxide as oxidant the dependences of initial rate of oxidation of both substrates (v0) on hydration degree W0 are characterized by maxima at W0 = 9-11, 20, and 41. In the system containing TBHP--ferritin these maxima were not observed. The parameters kcat, Km, and their ratios kcat/Km as a criterion of ferritin efficiency in peroxidase reactions were determined for both substrates in micellar medium at various W0. Increase of W0 was accompanied by a decrease of kcat and Km. With hydrogen peroxide the peroxidase activity of ferritin in the AOT micelles was significantly lower than in 0.1 M acetate buffer, pH 4.2. However, the efficiency (expressed as kcat/Km) of a system ferritin--Triton X-45-HP in micellar TMB oxidation exceeded that in the aqueous medium. A method of purification of iron-containing crystallite from the ferritin molecule was developed using reversed AOT micelles in heptane and heating the mixture on a water bath.
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PMID:Peroxidase activity of ferritin in aerosol OT reversed micelles in heptane. 986 54

The effects of combined oral contraceptives (OC), depot medroxyprogesterone acetate injections (DMPA), levonorgestrel subdermal implant (Norplant), copper-containing intrauterine devices (copper IUD), and Chinese stainless steel ring IUD on hemoglobin and ferritin were studied in 18-40-year-old, nonpregnant, and nonlactating women in seven countries (Bangladesh, Chile, China, the Dominican Republic, Pakistan, Thailand, and Tunisia). Data from 2507 women were analyzed. The study had a cross-sectional component in which 1295 current users of the contraceptive methods were compared with 1212 women initiating use of contraceptives. The results of this component showed that the current users of hormonal contraceptive methods generally had higher hemoglobin and ferritin levels than the noncontraceptors. The differences between women using hormonal contraceptive and noncontraceptors in mean values for hemoglobin varied between 3 and 6 g/L and for ferritin between 2 and 18 g/L. The current users of copper IUD had higher hemoglobin levels (difference in mean levels of 3 g/L), but lower ferritin levels (difference of 10 g/L) than noncontraceptors. Current use of the stainless steel ring had an adverse effect on both hemoglobin and ferritin. In a longitudinal component of the study, 285 anemic women (hemoglobin between 80 and 120 g/L at the time of initiation of contraception)--a subgroup of the cross-sectional component--were followed-up at 3, 6, and 12 months after initiation. In this component, significant mean increases of hemoglobin at 12 months were observed among the users of oral contraceptives and DMPA, but not among users of copper or stainless steel ring IUD. It is concluded that hemoglobin and ferritin levels are influenced by the use of contraceptives and that the hormonal contraceptives included in the present study have a beneficial effect on these parameters. The effects of copper IUD on hemoglobin and ferritin should be studied further.
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PMID:Effects of contraceptives on hemoglobin and ferritin. Task Force for Epidemiological Research on Reproductive Health, United Nations Development Programme/United Nations Population Fund/World Health Organization/World Bank Special Programme of Research, Development and Research Training in Human Reproduction, World Health Organization, Geneva, Switzerland. 988 81

In probing the possible non-genotoxic molecular mechanism(s) of nickel(II)-induced carcinogenesis, we performed a non-radioactive mRNA differential display analysis for nickel(II) acetate-treated Chinese hamster ovary cells (CHO-K1-BH4). Three out of thirty differentially expressed cDNAs had sequences highly similar to known genes. Down-regulation of vimentin and a hSNF2H homologue and up-regulation of ferritin heavy chain were confirmed by Northern blot analysis. The expression of these mRNAs was time- and nickel(II) concentration-dependent. For vimentin, the decrease in mRNA level was concurrent with a decrease in the protein level. For ferritin, the increase in mRNA had no effect on the protein level. Dysregulation of these gene products signifies their involvement in the epigenetic effects of carcinogenic nickel(II) compounds.
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PMID:Nickel(II) acetate-treated Chinese hamster ovary cells differentially express Vimentin, hSNF2H homologue, and H ferritin. 1032 30

The reactive metabolite(s) responsible for the expression of benzene toxicity is not clearly known despite extensive information on the metabolism and hematotoxicity of benzene. It is now widely believed that hematotoxicity of benzene is due to the concerted action of several metabolites which arise from multiple pathways of benzene. In our earlier study, we proposed iron polyphenol chelates as possible toxic metabolites of benzene due to their prooxidant activity. In continuation, we demonstrate the formation of an iron and 1,2,4-benzenetriol (BT) complex, when added together in an acetate buffer, 0.1 M, pH 5.6, by sephadex G-10 column chromatography. It was also observed that iron released from ferritin in the presence of BT formed a complex with BT.
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PMID:Complexation of 1,2,4-benzenetriol with inorganic and ferritin-released iron in vitro. 1033 34

We have previously demonstrated that phorbol myristate acetate (PMA) up-regulates H-ferritin gene expression in myeloid cells by stabilization of its message. In the present report, we showed that insertion of the 3'-untranslated region (3'-UTR) of H-ferritin mRNA at the 3'-end of luciferase coding sequence significantly reduced the stability of luciferase mRNA in human monocytic THP-1 cells. However, the half-life of the chimeric transcript was markedly prolonged after PMA treatment. A cytosolic protein factor from THP-1 cells was found to specifically bind to H-ferritin 3'-UTR. PMA treatment of THP-1 cells resulted in the reduction of the RNA binding activity in a time-dependent manner. Deletion analysis and RNase T1 mapping revealed a pyrimidine-rich sequence within the 3'-UTR which interacts with the protein factor. Competition experiments with homoribopolymers further demonstrated the importance of uridines for the binding activity. Point mutations in uridines of the pyrimidine-rich sequence reduced the protein binding to 3'-UTR, while increasing the stability of the chimeric luciferase transcript. Together, these results demonstrate that the pyrimidine-rich sequence in the 3'-UTR is involved in post-transcriptional regulation of H-ferritin gene expression in myeloid cells.
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PMID:Post-transcriptional regulation of H-ferritin mRNA. Identification of a pyrimidine-rich sequence in the 3'-untranslated region associated with message stability in human monocytic THP-1 cells. 1051 12

Genes induced or suppressed by oxidized low-density lipoproteins (oxLDL) in human monocytic THP-1 cells were searched using differential display reverse transcriptase polymerase chain reactions (DDRT-PCR). Among the many differentially expressed cDNA fragments, one was dramatically stimulated by the oxLDL in a steady state level, which was later found to contain sequences corresponding to ferritin light chain (L-ferritin) in a sequence homology search. The stimulatory effect of the oxLDL on the level of L-ferritin mRNA in the THP-1 cells was both time- and dose-dependent. When the cells were allowed to differentiate in the presence of phorbol 12-myristate 13-acetate (PMA), the differentiated cells were generally less responsive to the oxLDL than the undifferentiated ones. An increase of L-ferritin mRNA was observed when the cells were treated with the lipid components in the oxLDL such as 9-HODE, 13-HODE, and 25-hydroxycholesterol. In addition, a stimulation of the L-ferritin gene expression was also observed when the cells were treated with an endogenous peroxisome proliferator-activated receptor gamma (PPARgamma) ligand, 15d-PGJ2, in a time- and dose-dependent manner. These results suggest that oxLDL or its constituents are related to the stimulation of L-ferritin expression via PPARgamma.
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PMID:Regulation of ferritin light chain gene expression by oxidized low-density lipoproteins in human monocytic THP-1 cells. 1055 12

Polydisulfides of urea (PDSU), thiourea (PDSTU), biuret (PDSB), and gallic acid (PDSG) and their monomer analogues (urea, biuret, and gallic acid) inhibited (in a competitive manner) tetramethylbenzidine (TMB) peroxidation catalyzed by ferritin in 0.1 M acetate buffer, pH 4.2, containing 10% dimethylformamide. Their efficiency characterized in terms of inhibition constants, Ki, increased in the following order PDSU < PDSB approximately PDSTU << PDSG. This order is determined by the reactivity of monomers with respect to HO* radicals which are the main oxidizing agents in the system ferritin--H2O2. Polydisulfide antioxidants exhibit the intramolecular synergism of the inhibiting action (non-additivity of antiradical activity relative to their monomers) that was quantitatively characterized by alpha = (Ki)pol/(Ki)mon x n, where n is the number of monomers in the polymeric inhibitors. The alpha values increased from 1.5 up to 5.18 in the following order: PDSG < PDSU < PDSB. Significantly higher inhibiting efficiency of polydisulfide antioxidants as compared to monomer forms and synergism of the inhibitory action offer promising opportunities of their use as quenchers of free radical processes in biochemical systems.
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PMID:Intramolecular synergism of the inhibiting action of polydisulfide antioxidants in the system ferritin--H2O2--tetramethylbenzidine. 1056 69


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