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)

A brief exposure of low dose methylmercuric chloride to monolayer cultures of mouse fetal astrocytes caused a marked shift in the distribution of anionic groups on the surface membrane as evidenced by irregular disruption of cationized ferritin. It is suggested that one of the earliest changes following methyl mercury exposure in embryonic astrocytes includes alterations in the surface charge which may in turn trigger cascading toxic actions of methyl mercury in the developing brain.
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PMID:Surface charge alterations in mouse fetal astrocytes due to methyl mercury: an ultrastructural study with cationized ferritin. 369 41

Among the ferric compounds studied, cytochrome C, methemoglobin, lactoperoxidase, ferritin and ferric ion, in addition to catalase, had the ability to oxidize metallic mercury in the presence of hydrogen peroxide. On the other hand, hematin, the active center of catalase, did not oxidize metallic mercury. The results are consistent with the increased oxidation and uptake of mercury in the liver by acatalasemia mice.
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PMID:Mercury oxidation in vitro by ferric compounds. 711 84

Metalloproteins play structural and catalytic roles in gene expression. The metalloregulatory proteins are a subclass that exerts metal-responsive control of genes involved in respiration, metabolism, and metal-specific homeostasis or stress-response systems, such as iron uptake and storage, copper efflux, and mercury detoxification. Two allosteric mechanisms for control of gene expression were first discovered in metalloregulatory systems: an iron-responsive translational control mechanism for ferritin production and a mercury-responsive DNA-distortion mechanism for transcriptional control of detoxification genes. These otherwise unrelated mechanisms give rise to a rapid physiological response when metal ion concentrations exceed a dangerous threshold. Molecular recognition in these allosteric metal ion receptors is achieved through atypical coordination geometries, cluster formation, or complexes with prosthetic groups, such as sulfide and heme. Thus, many of the inorganic assemblies that otherwise buttress the structure of biopolymers or catalyze substrate transformation in active sites of enzymes have also been adapted to serve sensor functions in the metalloregulatory proteins. Mechanistic studies of these metal-sensor protein interactions are providing new insights into fundamental aspects of inorganic chemistry, molecular biology, and cellular physiology.
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PMID:Transition metals in control of gene expression. 834 37

With the single exception of mercury, all metals in the atmosphere are associated with particles. The lungs are subsequently exposed to metals present in air pollution particles on a continuous basis. Because metal exposure can be associated with an oxidative stress, a mechanism that isolates the metal in a chemically less reactive form would be of benefit. We tested the hypothesis that the concentrations of both lactoferrin and ferritin in the rat lung increase after exposure to a metal-rich emission source air pollution particle. Using immunohistochemistry, we characterized changes in the concentrations of ferritin and lactoferrin after exposure of rats to an emission source air pollution particle. Lavage metal concentrations, measured by inductively coupled plasma emission spectroscopy, increased 4 hr after exposure to an oil fly ash. After exposure to this metal-rich emission source air pollution particle, ferritin concentrations in the lower respiratory tract increased. Comparable to the iron-storage protein, concentrations of both lactoferrin and transferrin were elevated after exposure. The greatest concentrations of ferritin, lactoferrin, and transferrin occurred at approximately 24 hr after exposure to the air pollution particle. Levels then decreased, and by 96 hr after instillation of the oil fly ash, ferritin, lactoferrin, and transferrin were not elevated relative to those animals exposed to saline. We conclude that, in response to an emission source air pollution particle with high concentrations of metals, there is an increase in ferritin, lactoferrin, and transferrin concentrations in the lungs of the host. The function of these increases in iron-binding proteins may be to control the oxidative stress associated with the exposure to metals.
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PMID:Metal storage and transport proteins increase after exposure of the rat lung to an air pollution particle. 960 45

A temperature dependence of the corresponding signals, obtained by differential pulse (d.p.) and alternating current (a.c.) polarography, from a buffered aqueous solution of ferritin and beta 2-microglobulin is used for the characterization of a protein thermal denaturation process. The method is based on the significant differences in the interaction of folded and unfolded protein forms with a dropping mercury electrode due to a different accessibility, for the redox process, of protein electroactive groups. From the analysis of the resulting current, or capacitance, signals in function of temperature the thermal transition reversibility of different protein forms in the solution, protein melting points, and the apparent activation energies of the corresponding processes were determined.
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PMID:Polarographic investigation of beta 2-microglobulin and ferritin thermal denaturation. 987 Jan 89

The influence of occupational exposure to mercury vapours on the activity of the red cell enzymes [glucose-6-phosphate dehydrogenase (G-6PD), acetylcholinesterase (AChE), glutathione reductase (GR) and superoxide dismutase (SOD)], as well as on peripheral blood indices [erythrocyte number (RBC), HCT, Hb, MCHC] and on serum concentrations of iron, ferritin, transferrin and total iron binding capacity (TIBC), was assessed. Studies were carried out on 46 men aged between 21 and 56 years (X = 39 +/- 10.4) exposed to mercury vapours during their work from 7 months to 32 years (= 14.7 +/- 10.8). The control group consisted of 35 healthy workers aged between 20 and 54 years (X = 33.6 +/- 9.8) not exposed to chemical nor physical agents. In both groups studied, there were 50% and 34.3% smokers, respectively. The activity of studied red cell enzymes--G-6PD, AChE, GR and SOD--was estimated according to the colorimetric methods described by Beutler and expressed as international units per gram of hemoglobin (IU g Hb(-1)). Peripheral blood cell parameters were determined using an automatic cell counter. The concentration of serum iron and TIBC was determined using colorimetric methods (Beckman), while that of ferritin and transferrin by nephelometric methods. The time-weighted average (TWA) of mercury concentration in the air determined before the study was 0.0028 mg m(-3). Statistical analysis of the data was performed using either the Cochran and Cox C-test or the Student's t-test. The medium mercury concentration in the urine was 77.44 +/- 48.15 microg l(-1). In the group exposed to mercury vapours, a significant decrease was found in G-6PD activity (23.9%, P<0.001), GR (18.8%, P<0.001), and SOD (5%, P<0.001) with a concomitant increase in AChE activity (35.9%, P<0.001) was found. Moreover, a statistically significant increase occurred in HCT and RBC, and a decrease in MCV and MCHC as well as increases of ferritin (130.9%, P<0.001), transferrin (118.4%, P<0.001) and TIBC (11.2%, P<0.05). Our results indicate that long-term exposure to mercury vapours induces changes in the activity of red cell enzymes--G-6PD, AChE, GR and SOD--and may also influence other important hematological parameters of the peripheral blood.
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PMID:The activity of erythrocyte enzymes and basic indices of peripheral blood erythrocytes from workers chronically exposed to mercury vapours. 1079 23

Monoliths are considered to be the latest version of stationary phases for protein chromatography. They are now becoming popular since they exhibit reduced peak broadening due to low mass transfer resistances. A weak point of monoliths may be an inhomogeneous bed, especially when charged groups are present during co-polymerization. This becomes apparent when a protein solution is loaded onto such a monolith. A biphasic breakthrough curve differing from the sigmoidal-shaped one, is observed. Two error functions were used to approximate the breakthrough curve. From these parameters an estimate of the fraction of flow passing through the homogeneously packed part of the bed as well as the inhomogeneously one was derived. This flow pattern was also confirmed by perfusing ferritin through an inhomogeneous monolith and comparing it to an intact one. Electron microscopy and mercury porosimetry did not indicate any abnormalities in the bed.
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PMID:Control method for integrity of continuous beds. 1121 20

The aim of the present study was to investigate the G-1 uptake of mercury (Hg) after intake of a single dose of amalgam-Hg, followed by pharmacokinetic analysis of the data. Eleven volunteers without amalgam fillings ingested 1.00 g amalgam powder. Hg in plasma vs. time was analyzed with a two-compartment model by means of mixed-effects modeling. A fraction of the absorption rate of Hg to the central compartment was inversely proportional to the plasma ferritin levels. The population mean half-life of the terminal phase of Hg in plasma was 37 days, with a considerable standard deviation in the population. The absorbed fraction of the administered dose was estimated to be about 0.04%. It is concluded that the G-1 uptake of Hg is of quantitative importance during dental treatment.
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PMID:Mercury uptake and kinetics after ingestion of dental amalgam. 1192 35

Food is the main source of trace elements for the general population. The gastrointestinal absorption of certain trace elements, e.g., cadmium, is strongly influenced by iron (Fe) status. This factor may also be relevant for the bioavailability of other trace elements. Therefore, we investigated relationships between Fe status indicators and trace element concentrations in blood and serum of 234 boys and girls at ages 15 and 17 years. Fe status was measured using serum ferritin (S-Ft), soluble transferrin receptor in serum (sTfR), and the ratio sTfR/S-Ft. The trace elements we investigated were, in blood, cadmium, cobalt, copper, zinc, selenium, rubidium, mercury, and lead, and, in serum, cobalt, copper, zinc, selenium, rubidium, tungsten, mercury, and lead. We found inverse correlations between Fe status and blood cadmium, blood or serum cobalt, or blood copper. There were positive correlations between Fe status and mercury concentrations. Selenium was positively correlated with sTfR. The relationships between Fe status and lead were equivocal. There were fewer correlations for serum than for blood, but the inverse relationships between Fe status and cobalt were equally strong in serum and blood. We found only occasional, and perhaps spurious, correlations with zinc, rubidium, and tungsten. In conclusion, previous indications that cadmium, cobalt, and copper are absorbed by transport mechanisms similar to that of Fe are supported by this study. Strong positive correlations between Fe status and mercury concentrations remain to be explained.
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PMID:Iron status influences trace element levels in human blood and serum. 1582 Jul 28

Metal toxicity has been identified as a possible risk factor for amyotrophic lateral sclerosis (ALS) and other neurodegenerative disorders. We conducted a retrospective chart review of urinary, hair and blood metal levels and serum ferritin in 321 people with ALS seen over a ten-year period at the Massachusetts General Hospital (MGH). We found that hair lead levels and serum ferritin levels were elevated in ALS patients compared to published normal values. Metal levels of arsenic, lead, mercury, cadmium, thallium, cobalt and aluminum in 24-hour urine specimens and lead, mercury and arsenic in serum were within the normal range. We conclude that twenty-four hour urine or blood testing for metals is not warranted as part of the evaluation of ALS. Elevated levels of serum ferritin in ALS population could reflect an underlying perturbation in iron metabolism.
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PMID:Serum ferritin and metal levels as risk factors for amyotrophic lateral sclerosis. 1945 11


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