Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A procedure for trapping small molecules inside the interior of horse spleen ferritin (HoSF) and methods for characterizing HoSF and its small entrapped molecules are described. HoSF is first dissociated into subunits by adjustment to pH 2 in the presence of the small molecules to be trapped. The pH of the dissociated HoSF is then increased to 7 at which time the dissociated subunits reassemble reforming the 24-mer HoSF, thereby trapping solvent within its interior. HoSF is then separated from unbound molecules by dialysis, ultrafiltration, and/or ammonium sulfate precipitation. Sephadex G-25 and DEAE chromatographic methods were also used to separate HoSF from unbound small molecules. Capillary electrophoresis (CE) was used to demonstrate the association of small molecules with HoSF after the pH-induced unfolding-refolding process. The pH indicator neutral red was clearly associated with HoSF and presumed trapped within the ferritin interior. Acid/base titrations suggested that the trapped indicator had a different pKa than the free indicator, a result which indicates that the ferritin interior is different than the external solution. The utility of using trapped molecules for gaining information on ferritin function is proposed and discussed.
 ...
PMID:Molecular entrapment of small molecules within the interior of horse spleen ferritin. 811 6

We have reported previously that the heavy chain of ferritin is required for iron incorporation by ceruloplasmin (J.-H. Guo, M. Abedi, and S. D. Aust (1996) Arch. Biochem. Biophys. 335(1)). The purpose of this study was to determine how many heavy chains were required for ceruloplasmin to interact with ferritin such that iron loading occurred. The cDNA sequences encoding the heavy and light chains of rat liver ferritin were cloned into the baculovirus transfer vector pA-cUW51 under the control of polyhedrin and p10 promoters, respectively, which was then incorporated by homologous recombination into the infections Autographa californica nuclear polyhedrosis virus genome. Both ferritin chains were expressed and assembled into two heteropolymers following the infection of insect cells by recombinant virus, which were separated by DEAE-Sepharose chromatography. The percentage of heavy (H) and light (L) chains making up the two heteropolymers, determined by gel scanning following the resolution of chains on SDS-PAGE, were equivalent to 1 H and 23 L chains and 2 H and 22 L chains. The maximal extent of iron loading was observed using 1 mol of rat ceruloplasmin per mole of H chain in the two heteropolymers. The extent of iron incorporation decreased with additional ceruloplasmin. Iron incorporation into rat liver ferritin, found to contain 10 H chains, increased as the molar ratio of ceruloplasmin to ferritin increased to 4:1 and remained the same up to 8:1. Iron loading into horse spleen ferritin, found to have one H chain, appeared similar to that for recombinant ferritin, having only one H chain. Therefore, we propose that the optimal molar ratio of ceruloplasmin to ferritin depends upon the numbers of H chain making up the ferritin molecule for the maximal incorporation of iron into ferritin. These results also suggest that the iron loading channel is contained within a single H chain subunit.
 ...
PMID:Loading of iron into recombinant rat liver ferritin heteropolymers by ceruloplasmin. 916 16

The ferritins were purified from liver homogenates of buffalo, camel, cattle, sheep and shark by thermal denaturation, ammonium sulphate fractionation, Sephacryl S-300 gel filtration and DEAE-blue gel affinity chromatography. The yield and iron content of affinity-purified liver ferritins ranged from 0.008 to 0.052 mg/g and 3.17% to 11.4% respectively. As they are glycoproteins, the ferritins contained variable amounts of neutral carbohydrates. Except for shark ferritin, the ferritins all exhibited immunological cross-reactivity with anti-buffalo liver ferritin and anti-horse spleen ferritin by immunodiffusion and immunoelectrophoresis. Gel electrophoresis, gel filtration and ultracentrifugal analysis indicated the presence of a monomeric ferritin in all cases. SDS-gel electrophoresis of shark ferritin gave a protein band of 18 kDa. Ovine, buffalo and bovine ferritin comprised two protein subunits, the H (20 and 21 kDa) and the L types (18 and 19 kDa). Oligomeric ferritin subunits with molecular weights of 27, 37 and 55 kDa were also found for bovine and buffalo ferritin. SDS-PAGE of camel ferritin revealed a complex pattern with four prominent bands of 61, 51, 44 and 39 kDa. Two fast-migrating components of 15 and 16 kDa were also found in the purified liver ferritins, including reference preparations. The PO4(3-)/Fe ratios of purified shark (0.10) and bovine ferritin (0.12) were similar to that of standard equine spleen ferritin (0.11). However, the ratio was higher in ovine (0.17), camel (0.22) and bovine (0.26) ferritins. The amino acid compositions, molecular weights and sedimentation coefficients of the different liver ferritins were similar.
 ...
PMID:Purification and characterization of liver ferritins from different animal species. 1040 20

Camel kidney ferritin was isolated from a tissue homogenate by thermal denaturation, ammonium sulphate fractionation, Sephacryl S-300 gel filtration and DEAE-blue gel affinity chromatography. The yield and the iron and neutral carbohydrate contents were 0.012 mg/g wet tissue, 4.0% and 2.7%, respectively. The phosphate:iron ratio was 0.13, twofold lower than that reported for camel liver ferritin. Native gel electrophoresis revealed the presence of a monomeric ferritin. SDS gel electrophoresis and immunoblotting showed two types of subunits, heavy and light, contrary to the extensive heterogeneity observed in camel liver ferritin. In general, the tissue ferritins shared a similar amino acid composition. However, a twofold lower glycine and an eightfold higher arginine content were recorded for camel kidney ferritin. In addition, kidney ferritin had a relatively high content of glutamic acid. Cross-reactivity studies by Ouchterlony double diffusion and noncompetitive indirect ELISA revealed a distinct cross-reactivity between buffalo ferritin antiserum and camel liver ferritin, but camel liver ferritin showed only weak cross-reactivity.
 ...
PMID:Camel kidney ferritin: isolation and partial characterization. 1086 47

The pancreas ferritins from chickens, ducks, cattle and pigs were isolated by thermal denaturation, ammonium sulphate fractionation and DEAE-52 cellulose anion exchange chromatography separately, in order to obtain the characteristics both subunit types and isoelectric points. Four ferritins such as chicken pancreas ferritin (ChPF), duck pancreas ferritin (DPF), cattle pancreas ferritin (CaPF), and pig pancreas ferritin (PPF) showed different mobility in polyacrylamide gel electrophoresis (PAGE). The relative molecular masses (M(r)) of these ferritin were indicated to be M(r) (ChPF) > M(r) (DPF) > M(r) (CaPF) > M(r) (PPF), which are all bigger than that in horse spleen ferritin (HSF). Sodium dodecyl sulfate (SDS)-PAGE results indicate that ChPF, DPF, CaPF and PPF consist of H and L subunits, showing different ratios of H/L subunits. Two subunit types in the ferritin were further identified by peptide-mass fingerprinting (PMF) technology. The four ferritins such as ChPF, DPF, CaPF and PPF in denatured-isoelectric focusing (IEF) gel show the subunit polymers containing from 3 to 6 with different pI values, respectively. These phenomena reveal the complicated interactions and different polymers between H and L subunits in the ferritins. There are differences both interaction intensities and polymers in the ferritin subunits coming from different mammals. These heterogeneity may response to the rate of iron release in ferritins and to the detoxification requirement of iron in animals in vivo.
 ...
PMID:[Characteristics of subunit types and isoelectric points in four pancreas ferritins by electrophoresis and mass spectrometry]. 1944 50

Ferritin is nature's predominant iron storage protein. The molecule consists of a hollow protein shell composed of 24 subunits which is capable of storing up to 4500 iron atoms per molecule. Recently, this protein has been identified as a target molecule for increasing iron content in plant staple foods in order to combat dietary iron deficiency, a major public health problem in developing countries. Here, we present a novel technique for quantification of ferritin-bound iron in edible plant seeds using species-specific isotope dilution mass spectrometry (IDMS) by means of a biosynthetically produced (57)Fe-labeled ferritin spike and negative thermal ionization mass spectrometry (NTIMS). Native plant ferritin and added spike ferritin were extracted in 20 mM Tris buffer (pH 7.4) and separated by anion exchange chromatography (DEAE Sepharose), followed by isotopic analysis by thermal ionization mass spectrometry. The chosen IDMS approach was critically evaluated by assessing the (i) efficiency of analyte extraction, (ii) identical behavior of spike and analyte, and (iii) potential iron isotope exchange with natural iron. Repeatabilities that can be achieved are on the order of <5% RSD for quintuplicate analyses at an absolute detection limit of 60 ng of ferritin-bound iron for plant seeds. Studies in six different legumes revealed ferritin-iron contents ranging from 15% of total iron in red kidney beans up to 69% in lentils.
 ...
PMID:Quantification of ferritin-bound iron in plant samples by isotope tagging and species-specific isotope dilution mass spectrometry. 1965 60


<< Previous 1 2 3