Haemosiderin-like properties of free-radical-modified ferritin.
Ontology highlight
ABSTRACT:
SUBMITTER: O'Connell MJ
PROVIDER: S-EPMC1147411 | biostudies-other | 1986 Nov
REPOSITORIES: biostudies-other
Similar Datasets
Project description:A minor electrophoretically fast component was found in ferritin from iron-loaded rat liver in addition to a major electrophoretically slow ferritin similar to that observed in control rats. The electrophoretically fast ferritin showed immunological identity with the slow component, but on electrophoresis in SDS it gave a peptide of 17.3 kDa, in contrast with the electrophoretically slow ferritin, which gave a major band corresponding to the L-subunit (20.7 kDa). Thus the electrophoretically fast ferritin resembles that reported by Massover [(1985) Biochim. Biophys. Acta 829, 377-386] in livers of mice with short-term parenteral iron overload. The electrophoretically fast ferritin had a lower iron content (2000 Fe atoms/molecule) than the electrophoretically slow ferritin (3000 Fe atoms/molecule). Removal and re-incorporation of iron was possible without effect on the electrophoretic mobility of either ferritin species. On subcellular fractionation the electrophoretically fast ferritin was enriched in pellet fractions and was the sole soluble ferritin isolated from iron-laden secondary lysosomes (siderosomes). The amount and relative proportion of the electrophoretically fast species increased with iron loading. Haemosiderin isolated from siderosomes was found to contain a peptide reactive to anti-ferritin serum and corresponding to the 17.3 kDa peptide of the electrophoretically fast ferritin species. Unlike the electrophoretically slow ferritin, the electrophoretically fast ferritin did not become significantly radioactive in a 1 h biosynthetic labelling experiment. We conclude that the minor ferritin is not, as has been suggested for mouse liver ferritin, 'a completely new species of smaller holoferritin that represents a shift in the ferritin phenotype' in response to siderosis, but a precursor of haemosiderin, in agreement with the proposal by Richter [(1984) Lab. Invest. 50, 26-35] concerning siderosomal ferritin.
| S-EPMC1148141 | biostudies-other
Project description:Horse spleen and human spleen ferritins increase the formation of hydroxyl radicals (OH) at both pH 4.5 and pH 7.4 in reaction mixtures containing ascorbic acid and H2O2. The generation of OH is inhibited by the chelator desferrioxamine. Human spleen haemosiderin also accelerates OH generation in identical reaction mixtures, but is far less effective (on a unit iron basis) than ferritin under all reaction conditions. It is proposed that conversion of ferritin into haemosiderin in iron overload is biologically advantageous in that it decreases the ability of iron to promote oxygen-radical reactions.
| S-EPMC1146631 | biostudies-other
Project description:Iron release from both human and horse spleen haemosiderin to desferrioxamine was substantially less than that released from ferritin samples. This finding contradicts a previous report [Kontoghiorges, Chambers & Hoffbrand (1987) Biochem. J. 241, 87-92]. Differences in phosphate content of cores and in core size between haemosiderin and ferritin did not account for the different iron-release rates. Iron released to acetate was found to stimulate lipid peroxidation in liposomes, whereas that released to stronger chelators such as citrate and desferal did not. Absorption spectra and gel-filtration studies suggest that the acetate-solubilized iron was in the form of low-molecular-mass (less than 5 kDa) ferrihydrite fragments.
| S-EPMC1138761 | biostudies-other
Project description:Ferritin is a multisubunit protein that is responsible for storing and detoxifying cytosolic iron. Ferritin can be found in serum but is relatively iron poor. Serum ferritin occurs in iron overload disorders, in inflammation, and in the genetic disorder hyperferritinemia with cataracts. We show that ferritin secretion results when cellular ferritin synthesis occurs in the relative absence of free cytosolic iron. In yeast and mammalian cells, newly synthesized ferritin monomers can be translocated into the endoplasmic reticulum and transits through the secretory apparatus. Ferritin chains can be translocated into the endoplasmic reticulum in an in vitro translation and membrane insertion system. The insertion of ferritin monomers into the ER occurs under low-free-iron conditions, as iron will induce the assembly of ferritin. Secretion of ferritin chains provides a mechanism that limits ferritin nanocage assembly and ferritin-mediated iron sequestration in the absence of the translational inhibition of ferritin synthesis.
| S-EPMC3035985 | biostudies-literature
Project description:IntroductionPerioperative management of female patients undergoing breast surgeries differs from other patients due to chronic pain and postoperative nausea and vomiting. The anesthesia could consist of opioid-free general anesthesia (OFA) or non-opioid-free general anesthesia (NOFA). OFA relies on multimodal analgesia preoperatively and postoperatively. However, it is not yet established whether OFA could replace NOFA as a standard regimen for the management of breast surgeries. The aim of this study is to evaluate the efficacy of OFA for breast surgeries in female patients.Materials and methodsPatients undergoing modified radical mastectomy were retrospectively recruited. Two groups were defined: group 1, consisting of treated patients using OFA and group 2, consisting of treated patients using NOFA. Mean time to extubate and mean dose of morphine after recovery were computed. Postoperative morphine and antiemetic use were assessed for up to 24 h. A comparison of the computed data was conducted between both groups.ResultsA total of 116 patients were included with a mean age of 53±13 years. Group 1 consisted of 56 (mean age was 54±14 years). Group 2 consisted of 60 patients (mean age was 51±12 years). Demographic parameters and time to extubate did not yield significant differences. We noticed morphine sparing at T0 and T12 with statistically significant differences P=0.043 and P=0.006, respectively.ConclusionOFA could be considered in modified radical mastectomy management in female patients; nerve block seemed to act as morphine sparing in operative and postoperative settings by providing significantly less time to extubate with less postoperative morphine requirement.
| S-EPMC10473328 | biostudies-literature
Project description:1. Ferritin and haemosiderin in diluted tissue cannot be quantitatively separated by centrifugation unless the pH is brought below 6. 2. These iron-storage substances can be separated from one another and from haemoglobin by ion-exchange chromatography on CM-cellulose, when good recoveries of total tissue iron are obtained. 3. The ferritin fraction has been identified by its solubility, its appearance under the electron microscope, crystallization with Cd(2+) and the fact that it corresponds quantitatively to the heat-stable portion of the tissue non-haem iron.
| S-EPMC1215205 | biostudies-other
Project description:Ferritin and haemosiderin were shown, by the measurement of malondialdehyde production and loss of polyunsaturated fatty acids, to stimulate lipid peroxidation in liposomes. At pH 7.4 ascorbate was additionally required to achieve peroxidation; however, peroxidation occurred at pH 4.5 in the presence of iron-proteins alone. The damage was completely inhibited by the incorporation of chain-breaking antioxidants (alpha-tocopherol and butylated hydroxytoluene) into the liposomes. Metal chelators (desferrioxamine and EDTA) also completely inhibited lipid peroxidation. These and further results indicate that, at pH 4.5, even in the absence of a reducing agent, iron is released from haemosiderin and can mediate oxidative damage to a lipid membrane.
| S-EPMC1145159 | biostudies-other
Project description:Carvedilol is a widely prescribed drug for the treatment of heart failure and the prevention of associated ventricular arrhythmias. It has also been reported to function as a biological antioxidant via hydrogen atom transfer from its carbazole N-H moiety to chain-propagating radicals. Metabolites of the drug include phenolic derivatives, such as 3-hydroxy-, 4'-hydroxy- and 5'-hydroxycarvedilol, which are also potential antioxidants. A comparison of the radical-inhibiting activities of the parent drug and the three metabolites was carried out in two separate assays. In the first, hydrogen atom transfer from these four compounds to the stable radical DPPH was measured by the decrease in the UV-visible absorption at 515 nm of the latter. The known radical inhibitors BHT, 4-hydroxycarbazole and ?-tocopherol were employed as benchmarks in parallel experiments. In the second assay, inhibition of the photoinduced free-radical 1,2-addition of Se-phenyl p-tolueneselenosulfonate to cyclopropylacetylene, along with competing ring-opening of the cyclopropane ring, was monitored by 1H NMR spectroscopy in the presence of the carvedilol-based and benchmark antioxidants. In both assays, carvedilol displayed negligible antioxidant activity, while the three metabolites all proved superior radical inhibitors to BHT, with radical-quenching abilities in the order 3-hydroxy- > 5'-hydroxy > 4'-hydroxycarvedilol. Among the metabolites, 3-hydroxycarvedilol displayed even stronger activity in both assays than ?-tocopherol, the best of the benchmark antioxidants. These results suggest that the radical-inhibiting antioxidant properties that have been attributed to carvedilol are largely or exclusively due to its metabolites and not to the parent drug itself.
| S-EPMC6071783 | biostudies-literature
Project description:The heteroaromatic chelators 1,2-dimethyl-3-hydroxypyrid-4-one, maltol, mimosine and 2,4-dihydroxypyridine-N-oxide, have been shown to mobilize iron from human spleen haemosiderin, ferritin and also from iron(III) precipitates, all containing equal amounts of iron, at physiological pH. In the case of almost every chelator, the least-solubilized polynuclear iron form was ferritin, whereas haemosiderin was more soluble and the iron(III) precipitate the most soluble of all. Most of the chelators were more efficient than desferrioxamine at releasing iron from ferritin, but less efficient in the removal of iron from the other two polynuclear iron forms. It is suggested that the chelator differences in iron mobilization may be related to variations in the chelator molecular structure, the protein structure, iron forms and in the mechanism of iron release.
| S-EPMC1147528 | biostudies-other
Project description:The high catalytic activity of membrane-binding gold nanoparticles (AuNPs) makes its application in oxidation or reduction an attractive challenge. Herein, surface-functionalized bacterial cellulose (BC-poly(HEMA)) was successfully prepared with 2-hydroxyethyl methacrylate (HEMA) as monomers via the atom transfer radical polymerization (ATRP) method. BC-poly(HEMA) was further utilized as not only reducing agent but also carrier for uniform distribution of the AuNPs in the diameter of about 8 nm on the membrane surface during the synthesis stage. The synthesized AuNPs/BC-poly(HEMA) exhibited excellent catalytic activity and reusability for reducing 4-nitrophenol (4-NP) from NaBH4. The results proved that the catalytic performance of AuNPs/BC-poly(HEMA) was affected by the surrounding temperature and pH, and AuNPs/BC-poly(HEMA) maintained the extremely high catalytic activity of AuNPs/BC-poly(HEMA) even after 10 reuses. In addition, no 4-NP was detected in the degradation solution after being stored for 45 days. The reusable catalyst prepared by this work shows a potential industrial application prospect.
| S-EPMC6835580 | biostudies-literature