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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An apparatus consisting of two pumps, a mixer, a ferritin reactor, and a spectrophotometer was constructed to study the ability to trap various heavy metal ions (M2+) and the dynamics of a reconstituted ferritin reactor in flowing seawater. Reconstituted pig spleen ferritin (PSFr) is assembled from apo-protein shell to form a reconstituted iron core. The main components of the PSFr are its core, which contains an Fe2+:Pi stoichiometry of 6.0 +/- 0.5, reconstituted from pig spleen apoferritin (apo PSF), Fe2+, inorganic phosphate (Pi), and O2 (0.6 atm). The Fe3+-Pi clusters within the PSFr core exhibit resistance to salt ranging from 1% to 6% NaCl. The ferritin reactor consists of PSFr and an oscillating bag. Using the reactor, M2+ ions such as Cd2+, Zn2+, Co2+, and Mn2+ are directly trapped by the ferritin. We found a 1:2 +/- 0.2 stoichiometry of the trapped M2+ to the released iron as measured by chemical analysis or atomic absorption spectrometry; nontransient elements such as Na+, K+, Ca2+, etc., were scarcely trapped by the reactor. This study provides basic conditions for establishing a ferritin reactor and a convenient means for monitoring the pollution of heavy metal ions in seawater.
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PMID:Construction of a ferritin reactor: an efficient means for trapping various heavy metal ions in flowing seawater. 1119 68

Cubic F432 crystals of recombinant mouse L-chain apoferritin were obtained by the hanging-drop technique with ammonium sulfate and cadmium sulfate as precipitants. The structure was refined to 2.1 and 1.6 A resolution from data obtained at room temperature and under cryogenic conditions, respectively. The structure of an eight-amino-acid loop insertion in the mouse sequence is found to be highly disordered both at room temperature and at low temperature.
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PMID:Structure of mouse L-chain ferritin at 1.6 A resolution. 1167 11

The apparent fractional absorption of cadmium (Cd) from sunflower kernels (SFK) was determined in women volunteers by using kernels labeled with a stable isotope of Cd ((113)Cd) by injecting it into the flowering head. Fourteen women who were between the ages of 30 and 70 years, who did not use tobacco products, who were in good health, and who had been consuming a self-selected diet low in Cd content participated in the study. The volunteers were fed a breakfast composed primarily of cereal, milk, and fruit juice. The breakfast also contained a portion of (113)Cd-labeled SFK processed into a buttery spread. Each volunteer collected individual stool samples for 21 days beginning immediately after they had consumed the labeled kernels. The total amounts of Cd and (113)Cd excreted in each stool were determined by isotope dilution inductively coupled plasma mass spectrometry. Mean fecal Cd excretion was 14.1+/-4.1 microg/day and mean (113)Cd absorption was 10.6+/-4.4%. In agreement with previous studies, no significant (P>0.3) correlation between Cd absorption and serum ferritin concentrations was found in women whose serum ferritin concentrations were >25 ng/mL. These data suggest that the availability of Cd from highly processed sunflower kernels to humans is similar to that reported for other types of food.
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PMID:Cadmium absorption in women fed processed edible sunflower kernels labeled with a stable isotope of cadmium, (113)Cd. 1168 90

The first ferritin structure refined at the atomic level has been achieved on recombinant mouse L-chain apoferritin (rMoLF) crystals. These latter diffract to 1.2 A resolution under cryogenic conditions. When cryo-cooling the sample, the thermal disorder usually observed at room temperature is reduced and the low-temperature structure reveals several details concerning the protein putative active sites and their properties. Within the pores built up by the molecular three-fold symmetry axes, the iron entry route to the ferritin cavity, residues H118, D131 and E134, exhibit alternate conformations associated with the binding of partially hydrated cadmium ions, a metal used as a crystallization agent. At the mineral ferrihydrite nucleation center, the electron density maps evidence the orientation of E57, E60, E61 and E64 glutamate side chains (whereas they were observed highly disordered in previous ferritin structures determined at room temperature) and allow a description of the site taking into account the binding geometry of four Cd(2+) ions. Moreover, the side chain of residue K140, lying in the vicinity of the ferrihydrite nucleation center, is shown to interact with residue E61. As previously highlighted, this observation confirms the importance of K140 in the rMoLF sequence, as being responsible for the low level of iron incorporation by mousel L-chain ferritin compared to human L-chain ferritin. Finally, the diffusion of small molecules within the ferritin cavity is illustrated here by the presence of ordered molecules of glycerol used as a cryo-protectant, which bind the inner cavity surface of the protein.
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PMID:Structural description of the active sites of mouse L-chain ferritin at 1.2 A resolution. 1245 4

The liver pigmentary system of the frog Rana ridibunda was investigated after exposure to CdCl2. There was a time-dependent alteration in the area occupied by pigment cells. Most pigment was melanin, but lipofuscin and ferritin were also detected, being similarly increased with time. There was a time-dependent increase in the dimensions of pigment cells as a result of forming a cluster of more than two pigment cells, the so-called melanomacrophage aggregates (MMC). A thin capsule of connective tissue with fibroblast-like cells surrounds some MMCs. The various possible roles of MMCs are discussed, for instance, those of scavengers of foreign substances, for lowering of metabolic activities to survive in an anoxic environment probably caused by cadmium, or as scavenger of cadmium, thus playing a protective role against this metal.
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PMID:Impact of cadmium on liver pigmentary system of the frog Rana ridibunda. 1248 57

Comparative evaluation was made on alpha(1)-microglobulin (alpha(1)-MG), beta(2)-microglobulin (beta(2)-MG), retinol binding protein (RBP) and N-acetyl-beta-D-glucosaminidase (NAG), as a marker of renal tubular dysfunction after environmental exposure to cadmium (Cd), with special references to the effects of aging and correction for creatinine concentration. For this purpose, a previously established database of 817 never-smoking Japanese women (at the ages of 20 to 74 years) on hematological [hemoglobin, serum ferritin (FE), etc.] and urinary parameters [alpha(1)-MG, beta(2)-MG, creatinine (cr), and a specific gravity] was revisited. For the present analysis, the database was supplemented by the data on RBP and NAG in urine. The exposure of the women to Cd was such that the geometric mean Cd in urine was 1.3 microg/g cr. Among the four tubular dysfunction markers, NAG showed the closest correlation with Cd, followed by alpha(1)-MG and then beta(2)-MG, and RBP was least so although the correlations were all statistically significant. The observed values of the markers gave the best results, whereas correction for a urine specific gravity gave poorer correlation, and it was the worst when correction for creatinine concentration was applied. Age was the most influential confounding factor. The effect of age appeared to be attributable at least in part to the fact that both creatinine and, to a lesser extent, the specific gravity decreased as a function of age. Iron deficiency anemia of sub-clinical degree as observed among the women did not affect any of the four tubular dysfunction markers. In conclusion, NAG and alpha(1)-MG, rather beta(2)-MG or RBP, are more sensitive to detect Cd-induced tubular dysfunction in mass screening. The use of uncorrected observed values of the markers rather than traditional creatinine-corrected values is recommended when comparison covers people of a wide range of ages.
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PMID:Comparative evaluation of four urinary tubular dysfunction markers, with special references to the effects of aging and correction for creatinine concentration. 1284 88

Ferritin, in both crystalline and paracrystalline forms, occurs in the columnar epithelial cells of the dorsal wall of the radula of the marine chiton Cryptochiton stelleri, order, Polyplacophora. The ferritin occurs in association with the magnetite of the radular teeth. It has been isolated and crystallized in the presence of cadmium sulfate.
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PMID:INVERTEBRATE FERRITIN: OCCURRENCE IN MOLLUSCA. 1405 57

Isolated guts of Nereis diversicolor revealed the existence of a cadmium-binding protein, the MPII, belonging to the group of hemerythrins and myohemerythrins. The presence of MPII in the cells of the intestine was demonstrated by immunocytochemistry, using anti-MPII, a monoclonal antibody. In addition, using in situ hybridization and northern blotting, it was shown that MPII-cells are the site of synthesis of this molecule. Exposure of the worms to cadmium led to the cellular activation process of MPII-cells (i.e. transformation of the nucleolus, development of the endoplasmic reticulum and the Golgi apparatus), although MPII mRNA transcript levels were unchanged. Enzyme-linked immunosorbent assay (ELISA) of gut extracts revealed that MPII levels were increased after exposure to Cd, so it appears that this protein is synthesized as a response to Cd exposure without any new synthesis of mRNA. This mechanism of regulation is quite similar to that reported in the case of mammalian ferritin and may be involved in the regulation of Cd levels in this worm.
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PMID:Stimulation by cadmium of myohemerythrin-like cells in the gut of the annelid Nereis diversicolor. 1497 53

The influence of cigarette smoking, body iron store status and gender on cadmium (Cd) body burden was examined in a group of 197 healthy Thais with overall mean age of 30.5 year (19-47 year). The lowest, geometric mean, and the highest urinary Cd excretion rate was 0.04, 0.46 and 3.84 microg/g creatinine, respectively. The prevalence of low iron stores (serum ferritin <20 microg/l) was 16% and 2% in women and men, respectively. All women (n = 99) were non-smokers, but they had the same Cd body burden as did men (n = 47) who on average smoked 8.7 cigarettes per day for 9 years. These women and men had 1.9-fold greater body Cd burden than did non-smoking men (t = 4, P < 0.001). In addition, the women Cd body burden was found to be inversely correlated with serum ferritin (r = -0.39, P < 0.001) and those with low iron stores showed a 3.4-fold greater Cd body burden than did women whose serum ferritin being between 101 and 200 microg/l (F = 6.2, P = 0.003, one-way ANOVA). In contrast, men's Cd body burden did not show a significant correlation with serum ferritin, but it did show a positive correlation with cumulative cigarette smoking index (r = 0.29, P = 0.02). Thus, iron status and cigarette smoking were found to be determinants of Cd body burden in young adult Thai women and men.
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PMID:Influence of body iron store status and cigarette smoking on cadmium body burden of healthy Thai women and men. 1504 Oct 68

The absorption rate of dietary cadmium (Cd) was investigated among 38 female farmers who had been exposed to Cd at levels close to the current provisional tolerable weekly intake (PTWI); these levels were much higher than those examined in previous studies. The study group composed of 7 diabetics and their 13 age-matched controls and 6 anemic subjects and their 12 controls. With their informed consent, the study participants were confined in an inn for 7 nights and 8 days to collect all feces and urine and duplicates of all food consumed. The dietary Cd absorption rate was calculated for each subject from her total Cd intake and fecal excretion. The means and 95% confidence intervals (CI) of the diabetic group and the anemic group did not differ significantly from those of their respective controls. By individual analysis using all 38 subjects, however, significant Pearson's correlation coefficients were observed between Cd absorption rate and age, serum ferritin, serum iron, and blood and urine Cd levels. Among these, multiple regression analysis revealed that only age was a significant factor contributing to Cd absorption rate. The actual Cd absorption rate in the youngest age group (20-39 years) was 44.0%, which was highly accelerated compared with the rate in the total subject group of 6.5%, while zero to negative balance was observed in the older subjects. These results demonstrate that age, rather than iron deficiency, diabetes mellitus (DM), or Cd burden, is the only independent factor affecting the Cd absorption rate, suggesting that young women are always at high risk.
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PMID:Comprehensive study of the effects of age, iron deficiency, diabetes mellitus, and cadmium burden on dietary cadmium absorption in cadmium-exposed female Japanese farmers. 1569 66


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