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Query: UNIPROT:P06889 (
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630,302
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Poly(A) containing rat liver 21S RNA homogeneous in polyacrylamide gel electrophoresis under denaturing conditions and stimulating the synthesis of
ceruloplasmin
in a cell-free proteinsynthesizing system, was used as a template for reverse transcription in the presence of T10 primer and highly purified reverse transcriptase from avian myeloblastosis virus. The cDNA made this way was characterized by means of hybridization kinetics with mRNA, by melting of the hybrids formed and by chain length measurements. To increase the degree of representativity, the ceruloplasmin mRNA was fragmented by mild alkaline treatment, enzymatically polyadenylated and transcribed. The cDNA made was fully characterized and the kinetic complexity measured by hybridization with the mRNA was found to be equal to 2300 nucleotides as compared with the value of 3000 nucleotides is expected from gel electrophoresis data. The observed difference may indicate the presence of repeated sequences in the given mRNA. The sufficient representativitness of the synthesized cDNA and its specificity with respect to ceruloplasmin mRNA allows to use it as a molecular probe to study the
ceruloplasmin
gene structure.
Mol
Biol (Mosk)
PMID:[Enzymatic synthesis and characterization of DNA complementary to ceruloplasmin mRNA from rat liver]. 9 44
Highly purified preparations of mRNA coding for
ceruloplasmin
(CP) ere isolated from rat liver polyribosomes using indirect immunoprecipitation of CP polysomes and poly(U)-sepharose chromatography of polysomal RNA. The homogeneity of CP mRNA was as high as 86--90%. The molecular weight of CP mRNA is 1.3 . 10(6) daltons which is in excess when compared to the minimal size of mRNA necessary to code for CP precursor (about 700 amino acid residues). The base composition of CP mRNA is of AU-type. The experiments on end-labeling with [3H]borohydride after periodate oxidation whowed that CP mRNA contains 3'-terminal poly(A). Poly(U)-sepharose chromatography with stepwise temperature elution revealed length heterogeneity of poly(A) consisting of particular, different thermal subfractions of CP mRNA contain poly(A) consisting of 38, 90 and 165 adenylate residue. 5'-end of CP mRNA is block with inverted 7-methylguanosine (m7G) which is reducible with [3H]borohydride after periodate oxidation. This m7G residue is a component of RNAse- and alkali-resistant oligonucleotide, which structure according to net charge value and its shifts after various enzymatic treatments, is m7G5'ppp5'XmpAp.
Mol
Biol (Mosk)
PMID:[Physico-chemical characteristics of highly purified ceruloplasmin mRNA from rat liver]. 50 63
Ceruloplasmin, the blue copper-protein of vertebrate plasma, has been reviewed mainly from a functional point of view. However we have surveyed the chemistry and state copper in the molecule because of the implications of the recent data of Ryden (13,28). His observations suggest that unless special precautions are taken in the isolation of
ceruloplasmin
degradation, probably proteolytic, produces fragments of various sizes. When isolated, these fragments appear to be held together by noncovalent interactions. Comparison of their catalytic and spectral properties reveals no significant differences from a single homogeneous species of molecular weight of 134,000 isolated by Ryden's methods. On the other hand, the homogeneous molecule may differ in properties highly sensitive to conformation and three-dimensional parameters. Three types of copper atoms have been identified in
ceruloplasmin
, but their amino acid environment is still unknown. Ceruloplasmin possesses significant oxidase activity towards Fe(II) and numerous aromatic amines and phenols. Its
ferroxidase
activity has led to the discovery that it is a molecular link between copper and iron metabolism. Ceruloplasmin mobilizes iron into the plasma from iron storage cells in the liver. An equally important duty is that
ceruloplasmin
, after its rapid biosynthesis in the liver, serves as a major copper transport vehicle, comparable to transferrin. Evidence is accumulating that the copper atoms of
ceruloplasmin
are a prerequisite for copper utilization in the biosynthesis of cytochrome oxidase and other copper proteins. The ability of
ceruloplasmin
to release copper at specific cellular sites may be related to its broad substrate spectrum of biological reducing agents. A possible third role of
ceruloplasmin
is as a contributor to the regulation of the balance of biogenic amines through its oxidase action on the epinephrine and the hydroxyindole series. Thus
ceruloplasmin
is a copper-protein with several important functions, all of which are directly related to its oxidase activity.
Adv Enzymol Relat Areas
Mol
Biol 1976
PMID:Ceruloplasmin: the copper transport protein with essential oxidase activity. 77 38
Partially purified ceruloplasmin mRNA was isolated using indirect immunoprecipitation of rat liver polysomes and poly(U)-Sepharose chromatography of polysomal RNA. This RNA programmed the synthesis of
ceruloplasmin
polypeptides in a cell-free system from mitochondria. Immunochemical analysis of the translation products revealed a 40-fold enrichment of the ceruloplasmin mRNA activity. The purified ceruloplasmin mRNA migrated as a major homogeneous component with an apparent molecular weight about 1 X 10(6) daltons in polyacrylamide gels containing sodium dodecyl sulfate. The immunoprecipitated products of the cell-free translation had molecular weights in the range 4.5--5.4 X 10(4) daltons as estimated by gel-electrophoresis under denaturating conditions. These values approach the weight of the half-molecule of native
ceruloplasmin
.
Mol
Biol Rep 1977 Mar
PMID:Isolation and partial purification of ceruloplasmin messenger RNA from rat liver. 87 Aug 19
Phenotypes of the cells developing into small colonies after days of primary culture of adult rat hepatocytes in serum-free modified Dulbecco Modified Eagles' medium containing 10 mM nicotinamide and 10 ng/ml epidermal growth factor were analyzed immunocytochemically, cytochemically and ultrastructurally. Albumin, cytokeratin 8 and 18 were seen by immunocytochemical techniques in the cells of the small colonies at Day 6. Transferrin, alpha 1-antitrypsin,
ceruloplasmin
, and haptoglobin, proteins secreted by mature hepatocytes, were faintly stained in these cells as was alpha-fetoprotein. These proteins were secreted into the culture medium as evidenced by immunoblot analysis. gamma-Glutamyltransferase, alkaline phosphatase and glucose 6-phosphatase were not present in the cells of the small colonies as well as the surrounding hepatocytes at Day 6 of culture. In addition, ultrastructural examinations of the cells in the small colonies indicated that these cells not only had many characteristic mitochondria and desmosomes, but also a few small peroxisomes. Such cells, even after 20 days in culture were proliferating, as evidenced by the intranuclear presence of the proliferating cell nuclear antigen. The potential relation of these cells to hepatocytes which may serve as the principal reserve for replicating hepatocytes is discussed.
Virchows Arch B Cell Pathol Incl
Mol
Pathol 1992
PMID:Characteristics of small cell colonies developing in primary cultures of adult rat hepatocytes. 127 92
The concentration of copper in the livers of Long-Evans rats with cinnamon-like coat color (LEC), in which hepatitis and then hepatomas develop spontaneously, was recently found to be abnormally high. Therefore, we examined the copper concentrations in the livers of LEC F1 backcrosses (LEC F1 x LEC) to determine the linkage of copper accumulation with development of hepatitis. Consistent with a previously reported ratio of rats with hepatitis to rats without hepatitis of about 1:1, hepatitis developed in 14 of 30 F1 backcrosses. The copper concentrations in the livers of all LEC F1 backcrosses with hepatitis were abnormally high and comparable to those of LEC rats. In contrast, the concentrations in all backcrosses without hepatitis were similar to those in normal Long-Evans with agouti coat color or Brown-Norway rats. Copper accumulation was shown to be closely linked with the development of hepatitis in LEC rats and appeared to be a possible cause of hepatitis. The concentrations of copper in the livers of Fischer 344 rats after carbon tetrachloride treatment were in the range for normal liver, indicating that a high copper concentration in the liver is specific to LEC rats and not a specific characteristic of hepatitis. Furthermore, we found that the size and level of ceruloplasmin mRNA in the livers of LEC rats were the same as those in LEA rats and that the size and level of
ceruloplasmin
polypeptide in their livers and plasma were almost the same as those in LEA rats. Therefore, these results suggest that the copper accumulation is not due to alteration of expression or to gross alteration of the
ceruloplasmin
gene.
Mol
Carcinog 1992
PMID:Genetic linkage between copper accumulation and hepatitis/hepatoma development in LEC rats. 131 58
Recombinant clones of Schistosoma mansoni cDNA libraries containing the complete coding regions of 2 different ferritin subunits have been isolated and sequenced. This allows for the first time a comparison of ferritin sequences from an invertebrate with those of vertebrates. The deduced amino acid sequences of both Schistosoma ferritin subunit clones show significant homology to vertebrate ferritin H chains. Similarity exceeds 50% identity and includes the recently identified
ferroxidase
center which is present only in H chains. However, non-conservative substitutions of amino acid residues lining the 3-fold symmetry channel were found, and a gap of 3 successive amino acids unique to the 2 Schistosoma ferritin sequences was identified. Remarkably, for each of the 2 genes, we found a conspicuous difference in the amount of ferritin transcripts between females and males: one of the genes is preferentially expressed in females, the other in males.
Mol
Biochem Parasitol 1992 Feb
PMID:Ferritins of Schistosoma mansoni: sequence comparison and expression in female and male worms. 174 Oct 11
The structure and crystal chemical properties of iron cores of reconstituted recombinant human ferritins and their site-directed variants have been studied by transmission electron microscopy and electron diffraction. The kinetics of Fe uptake have been compared spectrophotometrically. Recombinant L and H-chain ferritins, and recombinant H-chain variants incorporating modifications in the threefold (Asp131----His or Glu134----Ala) and fourfold (Leu169----Arg) channels, at the partially buried
ferroxidase
sites (Glu62,His65----Lys,Gly), a putative nucleation site on the inner surface (Glu61,Glu64,Glu67----Ala), and both the
ferroxidase
and nucleation sites (Glu62,His65----Lys,Gly and Glu61,Glu64,Glu67----Ala), were investigated. An additional H-chain variant, incorporating substitution of the last ten C-terminal residues for those of the L-chain protein, was also studied. Most of the proteins assimilated iron to give discrete electron-dense cores of the Fe(III) hydrated oxide, ferrihydrite (Fe2O3.nH2O). No differences were observed for variants modified in the three- or fourfold channels compared with the unmodified H-chain ferritin. The recombinant L-chain ferritin and H-chain variant depleted of the
ferroxidase
site, however, showed markedly reduced uptake kinetics and comprised cores of increased diameter and regularity. Depletion of the inner surface Glu residues, whilst maintaining the
ferroxidase
site, resulted in a partially reduced rate of Fe uptake and iron cores of wider particle size distribution. Modification of both
ferroxidase
and inner surface Glu residues resulted in complete inhibition of iron uptake and deposition. No cores were observed by electron microscopy although negative staining showed that the protein shell was intact. The general requirement of an appropriate spatial charge density across the cavity surface rather than specific amino acid residues could explain how, in spite of an almost complete lack of identity between the amino acid sequences of bacterioferritin and mammalian ferritins, ferrihydrite is deposited within the cavity of both proteins under similar reconstitution conditions.
J
Mol
Biol 1991 Oct 20
PMID:Influence of site-directed modifications on the formation of iron cores in ferritin. 194 61
The influence of rat round spermatid protein(s) (RSP) on protein synthesis and secretory function of Sertoli cells was used in the bicameral chamber system. Round spermatids (RS) were purified from 90-day-old rats by centrifugal elutriation. RS were incubated in a supplement-enriched culture medium that lacked exogenous proteins. The RS-conditioned media were dialysed and lyophilized to obtain RSP. Most de novo protein synthesized under basal conditions by Sertoli cells (18-day-old) was secreted into the apical chamber (apical/basal ratio: 3.42). Follicle-stimulating hormone (FSH, 100 ng/ml) stimulated total protein secretion from Sertoli cells by a factor of 1.54. The RSP (100 micrograms/ml) stimulated total protein secretion from Sertoli cells by a factor of 2.33. The enhancement of total Sertoli cell protein secretion by FSH and RSP additively increased by a factor of 2.82. The combined effect of FSH and RSP on total protein secretion from Sertoli cells was dose dependent and saturated at approximately 200 micrograms/ml of RSP. Polarity of total protein secretion from Sertoli cells (apical/basal ratio: 3.42) was stimulated by RSP predominantly in the apical direction (apical/basal ratio: 8.48). The modulation of radiolabeled Sertoli cell secretory proteins (
ceruloplasmin
, CP; sulfated glycoprotein-2, SGP-2; testins and transferrin, Tf) by cold (non-labeled) RSP was investigated by immunoprecipitation followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The secretion of CP, SGP-2 and Tf was stimulated in a dose-dependent manner by the addition of RSP up to a saturating concentration of between 200 and 300 micrograms/ml, whereas the secretion of Sertoli cell testins did not reach saturation at 300 micrograms/ml RSP. These results indicate that FSH and RSP independently modulate Sertoli cell protein secretion, and that Sertoli cell secretory proteins may differentially respond to RSP stimulation.
Mol
Cell Endocrinol 1990 Oct 01
PMID:Modulation of Sertoli cell secretory function by rat round spermatid protein(s). 212 59
Expression of
ceruloplasmin
(Cp)-coding gene in rat and human liver and brain tissues was studied by Northern blot hybridization and by in situ hybridization with cloned species-specific cDNA probes. In rat brain structures, different levels of Cp mRNA were detected, the maximal one was found in cerebellum. The steady-state level of Cp mRNA in rat and human brain was several times lower than in parenchymatous liver cells. The size heterogeneity of Cp mRNA was found. Polyadenylated RNA prepared from human liver contains two equally abundant Cp mRNAs differing in their chain length (3.6 and 4.5 kb) while brain polyadenylated RNA contains a single Cp mRNA (4.5 kb).
Mol
Biol (Mosk)
PMID:[Expression of ceruloplasmin gene in mammalian organs from the data of hybridization analysis with complementary DNA probes]. 240 35
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