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PubMed1985

Serum copper, serum ceruloplasmin, and erythrocyte sedimentation rate measurements in children with Hodgkin's disease, non-Hodgkin's lymphoma, and nonmalignant lymphadenopathy.

Between 1975 and 1981, 29 children with Hodgkin's disease, 22 with non-Hodgkin's lymphoma, and 13 with lymphadenopathy from various nonmalignant causes were studied with respect to the usefulness of serum copper, ceruloplasmin, and erythrocyte sedimentation rate (ESR) as markers of disease activity. Although elevated copper and ceruloplasmin levels were indicators of disease activity in the childhood lymphomas, and in patients with Hodgkin's disease the levels tended to be higher in those with advanced clinical stage, they were no better markers of disease activity than the ESR. Moreover, elevated serum copper and ceruloplasmin were nonspecific, since one child with benign lymphadenopathy and one Hodgkin's disease patient with an infection had raised levels. Low levels of copper and ceruloplasmin were found in four jaundiced patients probably because of impaired hepatic synthesis of ceruloplasmin. The authors conclude that serum copper and ceruloplasmin levels are no better markers of disease activity in children with lymphomas than is the ESR.

Adolescent↗

PubMed1988

Heterogeneity in copper and glycan content of ceruloplasmin in human serum differs in health and disease.

Crossed immunoelectrophoresis of human serum revealed two heterogeneity types of ceruloplasmin with different electrophoretic migration. The two types both consisted of peptides with Mr 150,000, 100,000 and 45,000, which were interpreted as native ceruloplasmin and two hydrolytic fragments. The two types were different in copper content, and one type could reversibly be changed into the other. The glycan microheterogeneity of ceruloplasmin was analyzed by crossed affinoimmunoelectrophoresis with free Lens culinaris agglutinin (LCA) and wheat germ agglutinin (WGA). A third of the ceruloplasmin molecules, both high and low copper type, bound to LCA and two thirds to WGA. The heterogeneity and the microheterogeneity of ceruloplasmin in two groups of patient sera were compared to sera from healthy individuals. The ceruloplasmin type with respect to copper content was a much better factor than either glycan microheterogeneity or total serum concentration in discriminating between the three groups.

Ceruloplasmin↗

PubMed1994

Isolation of nonlabile human ceruloplasmin by chromatographic removal of a plasma metalloproteinase.

Ceruloplasmin (EC 1.16.3.1) is a copper-containing alpha 2-glycoprotein and a member of the acute phase reactant family. Fragmentation of ceruloplasmin during purification and storage has hampered studies of its structure, but it has been shown to be a 132-kDa monomer. Combining two published chromatographic steps with additional gel filtration and fast protein liquid chromatography (FPLC) steps, we now report a procedure that yields a highly purified and nonlabile protein. Human plasma was subjected to QAE-Sephadex A-50 chromatography, precipitated with ammonium sulfate, and chromatographed on a hydroxyapatite column. The resulting protein was > 95% pure but highly unstable as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis; at 37 degrees C the 132-kDa protein disappeared completely within 48 h. Further purification of ceruloplasmin by Sephadex G-50 chromatography and Mono Q FPLC yielded a protein that was essentially pure by multiple criteria and completely stable even after incubation at 37 degrees C for 4 weeks. When purified ceruloplasmin was reconstituted with fractions eluted from the Sephadex G-50 column, a single fraction induced proteolytic degradation. The degradation of ceruloplasmin by this fraction was inhibited by EDTA and 1,10-phenanthroline, indicating that a plasma metalloproteinase is responsible for degradation of ceruloplasmin.

Ammonium Sulfate↗

PubMed1997

Loading of iron into recombinant rat liver ferritin heteropolymers by ceruloplasmin.

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.

Animals↗

PubMed1996

Divalent cation binding to ceruloplasmin.

Binding of calcium to human and sheep ceruloplasmin was investigated by metal substitution with manganese and competitive displacement of bound manganese by calcium monitored by electron paramagnetic resonance spectroscopy. The Kd for calcium was found to be 1.4 mM. Magnesium also bound to ceruloplasmin, with Kd = 0.3 and 0.7 mM for the human and sheep protein, respectively. The thermal stability of ceruloplasmin, as studied by differential scanning calorimetry, was affected by calcium but not by magnesium. A considerable increase of the Tm value, from 73.8 to 83.1 degrees C, was observed for sheep ceruloplasmin in the presence of calcium. The Tm value of the human protein was only slightly altered by calcium (from 85.1 to 87 degrees C). The interaction of ceruloplasmin with the chromatographic material used for its isolation, Sepharose 4B derivatized with chloroethylamine, was weakened by calcium. This allowed us to set up a novel purification scheme that made it possible to efficiently isolate ceruloplasmin and prothrombin from plasma with the same single-step chromatography.

Animals↗

PubMed1983

Isolation and characterization of copper-binding sites of human ceruloplasmin.

A tryptic cleavage procedure was used to obtain stable copper-containing peptide regions of human ceruloplasmin. Tryptic digestion-derived copper peptides were fractionated by gel filtration chromatography, yielding two fractions, one with an apparent molecular weight of 11000 and the other 1000. The high molecular weight fraction (11K fraction) was found to contain 50% of the copper atoms of the ceruloplasmin molecule and behaved as a single copper-containing component by gel filtration chromatography and by isoelectric focusing. The low molecular weight fraction (1K fraction) was found to be a mixture of three or four copper peptides by isoelectric focusing. Acrylamide gel electrophoresis studies, amino acid composition analysis and terminal amino acid determinations showed the 11K fraction to be a complex composed of at least three peptides arising from different regions of the ceruloplasmin molecule. Two of the peptides of the 11K complex appear to be derived from the 19K fragment of the ceruloplasmin molecule (18); one peptide in the complex appears to correspond to the aspartic acid-rich portion, residues 7-30, and the other to the histidine-rich portion, residues 103-157. Most preparations of ceruloplasmin are reported to consist of three non-covalently linked fragments that have molecular weights of 67K, 50K and 19K. Dwulet and Putnam (20) proposed a model for the sequence structure of ceruloplasmin where the molecule exhibits a three-fold repeat pattern of two alternating structures, here termed X and Y.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗

PubMedDate not supplied

An enzyme-linked immunoadsorbent assay for rat ceruloplasmin.

A noncompetitive, colorimetric enzyme-linked immunoadsorbent assay (ELISA)+ was developed for measuring rat ceruloplasmin in serum and in medium from culture hepatocytes. The assay utilized polystyrene immobilized antibody which bound ceruloplasmin which then bound biotinylated antibody. The biotinylated antibody-antigen complex was detected with strepavidin-alkaline phosphatase conjugate. Standard curves for rat ceruloplasmin were constructed in the range between 10 and 50 ng/mL. Increases of 10 ng produced an increase in A403 of more than 0.2. With this immunoassay, serum ceruloplasmin levels were found to average 35 mg Cp/dL in control rats and 87 mg/dL in rats with experimental inflammation. Liver parenchymal cells secreted 1.6 micrograms Cp/5 x 10(5) cells/24 h. This ELISA assay for ceruloplasmin will facilitate studies on the regulation of ceruloplasmin synthesis and secretion in both intact rats and isolated hepatocytes.

Animals↗

PubMed1985

The expression of ceruloplasmin, an angiogenic glycoprotein, by mouse embryonic fibroblasts.

Balb/c 3T3, Swiss 3T3 and Rous sarcoma virus transformed Balb/c 3T3 mouse embryonic fibroblasts produced ceruloplasmin in vitro, whereas primary cultures prepared from the Balb/c mouse embryos did not produce ceruloplasmin. The amount of ceruloplasmin synthesis by the Balb/c 3T3 cell line is enhanced by Rous sarcoma virus-transformation (1.5-3 fold) and by treatment with dexamethasone (about 2.4 fold). The protein was identified as ceruloplasmin by immunoprecipitation with ceruloplasmin-specific polyclonal antibody, and by similarity of peptide maps, and subunit molecular weight (135,000 dalton) to that of authentic ceruloplasmin from primary cultures of mouse hepatocytes.

Animals↗

PubMed1985

Secretion of ceruloplasmin by a human clear cell carcinoma maintained in nude mice.

Ceruloplasmin is the best known but least understood copper protein. Studies preliminary to investigating the control of ceruloplasmin synthesis have utilized a human renal cell carcinoma maintained in nude mice for 73 passages over a 5-year period. In vitro cultures of these cells were accomplished and the mRNAs were extracted prior to microinjection into Xenopus oocytes. The media examined by SE-HPLC and immunological techniques demonstrated that (1) after in vitro culture, ceruloplasmin was secreted as an uncleaved polypeptide chain with a MW of 135,000; (2) the translational product of ceruloplasmin mRNA injected into Xenopus oocytes was cleaved into fragments with MWs of 110,000, 67,000, and 50,000. The results indicate that mRNA for human ceruloplasmin can be obtained to serve as a template for the synthesis of a cDNA probe to investigate the control of human ceruloplasmin's synthesis.

Adenocarcinoma↗

PubMed1993

Deficiency of holo-, but not apo-, ceruloplasmin in genetically copper-intoxicated LEC mutant rat.

Long-Evans Cinnamon(LEC) mutant rats exhibited less than 5% of normal levels of serum ceruloplasmin oxidase activity, but immunoblot analysis showed normal levels of immunologically detectable ceruloplasmin protein in sera from the mutant rats. Immunostaining of cryosections from the liver tissues with anti-ceruloplasmin antibody showed no significant difference between normal and LEC rats. Results from pulse labeling of ceruloplasmin for 3 hours with [35S]methionine in primary hepatocyte culture, followed by immunoprecipitation, SDS-PAGE and fluorography, showed only minor changes in ceruloplasmin protein synthesis and secretion. These results suggest that the mutation(s) does not affect ceruloplasmin gene expression, but results in a failure in the mechanism whereby copper is incorporated into newly synthesized apoceruloplasmin to produce oxidase active holoform.

Animals↗

PubMed1984

The reaction of cysteine with ceruloplasmin copper.

The kinetics of decay in absorbance at 610 nm in the reaction of cysteine with ceruloplasmin was biphasic under anaerobic conditions. Admission of oxygen to the bleached ceruloplasmin restored the blue color to about 75% of the original value. However, under aerobic or anaerobic conditions an initial bleaching corresponded to a 25% decrease in blue color. This change was irreversible and remained after removal of excess cysteine from the reaction mixture by dialysis. There was no correlation between transient and steady-state kinetic parameters. Circular dichroism measurements showed a characteristic reduction in the negative band at 450 nm, which is specific for type 1b copper. Isolation and further studies on cysteine-modified ceruloplasmin with a lower A610/A280 ratio showed less than 10% reduction in enzyme activity toward p-phenylenediamine and o-dianisidine. Evidence is also presented that ceruloplasmin catalyzes the oxidation of cysteine with a one-electron reduction of oxygen and the formation of superoxide ion, which is then converted to H2O2 by ceruloplasmin. The effect of superoxide dismutase and catalase also confirms the presence of superoxide and H2O2. In sum, these data show that a permanent reduction of type 1b copper occurred when cysteine was used as a substrate. We conclude that there is a single electron transfer from cysteine directly to oxygen using one specific copper of ceruloplasmin, type 1b.

Animals↗

PubMed1994

Increased bilirubin production, ceruloplasmin concentrations and hyperbilirubinaemia in full-term newborn infants.

Ceruloplasmin possesses antioxidant activity in vitro, but such a property has not been substantiated in vivo so far. However, it has been suggested that the lack of factors protective against oxidative haemolysis might have a role in neonatal hyperbilirubinaemia. Ceruloplasmin and alphafetoprotein concentrations were measured in cord blood in 78 unselected full-term singleton newborn infants without G6PD deficiency and haemolytic disease of the newborn; in the same infants, the carboxyhaemoglobin level was assessed on the fourth day of life and taken as an index of bilirubin production. The relationship between these variables and maximum bilirubin level in the first 4 days was studied by multiple regression analysis. High carboxyhaemoglobin levels and low ceruloplasmin concentrations, but not alphafetoprotein resulted, associated with hyperbilirubinaemia (P < 0.001). No relationship was found between carboxyhaemoglobin and ceruloplasmin levels. These results exclude an important role for ceruloplasmin in protecting against possible oxidative haemolysis in full-term newborn infants. Ceruloplasmin levels in cord blood are most probably related to hepatic metabolism and are better predictors of hyperbilirubinaemia than alphafetoprotein concentrations.

Bilirubin↗

PubMed1984

Ceruloplasmin receptors of erythrocytes.

Mammalian erythrocytes have been shown to bind 125I labeled ceruloplasmin. Binding was reversible and specific. Scatchard analysis yielded linear plots with a Kd of approximately 5nM. The binding site appeared to be a protein located on the cell surface. A ceruloplasmin binding protein with a molecular weight of 60,000 daltons was isolated from human erythrocytes. Erythrocytes which were not protected by ceruloplasmin's antioxidant properties, did not bind ceruloplasmin. Our results provide evidence for the presence of ceruloplasmin receptors in the erythrocyte membrane. It is proposed that the antioxidant activity of ceruloplasmin may play a role in determining the lifespan of circulating red cells.

Animals↗

PubMed1998

Thiol-linked peroxidase activity of human ceruloplasmin.

Human ceruloplasmin exhibited different antioxidant effects according to the electron donors in a metal-catalyzed oxidation system. Purified ceruloplasmin did not play a significant role in the protection of DNA strand breaks in the ascorbate/Fe3+/O2 system. However, when ascorbates were replaced with a thiol-reducing equivalent such as dithiothreitol, DNA strand breaks were significantly prevented by the same amount of ceruloplasmin. Ceruloplasmin did not catalyze the decomposition of H2O2 in the absence of reduced glutathione. On the contrary, ceruloplasmin showed a potent peroxidase ability to destroy H2O2 in the presence of reduced glutathione. In conclusion, the removal of H2O2 by human ceruloplasmin is not simply stoichiometric but thiol-dependent.

Antioxidants↗

PubMed2000

Fragmentation of human ceruloplasmin induced by hydrogen peroxide.

We investigated the fragmentation of human ceruloplasmin induced by H2O2 to study its oxidative damage. When ceruloplasmin was incubated with H2O2, the frequency of the protein fragmentation increased in a proportion to the concentration of H2O2. It also increased in a time-dependent manner and was accompanied by gradual loss of the oxidase activity. Hydroxyl radical scavengers such as azide and mannitol inhibited the fragmentation of ceruloplasmin. The deoxyribose assay showed that hydroxyl radicals were generated in the reaction of ceruloplasmin with H2O2. Incubation of ceruloplasmin with H2O2 resulted in a time-dependent release of copper ions. The released copper ion may participate in a Fenton-like reaction to produce hydroxyl radical, which enhanced the fragmentation. The protection of the fragmentation by copper chelators such as diethylenetriaminepentaacetic acid and bathocuproine indicates a role for copper ion in the reaction. These results suggest that the fragmentation of ceruloplasmin induced by H2O2 is due to hydroxyl radicals formed by a copper-dependent Fenton-like reaction.

Ceruloplasmin↗

PubMed1997

Serum ceruloplasmin as a diagnostic marker of cancer.

The pursuit of the ideal tumor marker has generated many tests for use in the diagnosis and management of cancer, several of which are now widely available. The objective of this study was to evaluate the diagnostic utility as a cancer marker of plasmatic levels of ceruloplasmin. Ceruloplasmin is a glucoprotein that transports serum copper. A case-control design was used. Serum values were evaluated in 144 patients and 103 normal controls by receiver operating characteristic (ROC) curve analysis to define the optimal cut-off levels for the serum values of ceruloplasmin in the diagnosis of cancer. The ROC analysis showed that ceruloplasmin is considerably sensitive in men (80%) at the specificity level of 80.3% and in women the sensitivity (Se) was (63.2%) and the specificity (Sp) was (63.3%). According to this study, it would seem optimal to use the cut-off level of 358 mg/l in men and 383 mg/l in women. In conclusion, serum ceruloplasmin was significantly elevated in advanced stages of solid malignant tumors, however, locally advanced or locoregionally spreading tumors did lead to significant increases (P < 0.01). Finally, the results of ROC curve analysis suggest that the ceruloplasmin is characteristic of good diagnostic markers.

Adolescent↗

PubMed1986

Ceruloplasmin, extracellular-superoxide dismutase, and scavenging of superoxide anion radicals.

Ceruloplasmin and extracellular-superoxide dismutase are similar in physical properties. Both are found in extracellular fluids and both are scavengers of the superoxide radical. The relationship between the two proteins was further explored in the present investigation. Ceruloplasmin preparations were found to be commonly contaminated with extracellular-superoxide dismutase. In one preparation, 80% of the superoxide dismutase activity was due to extracellular-superoxide dismutase. Ceruloplasmin, freed from contaminating superoxide dismutase, was found to catalytically dismute the superoxide anion radical with a rate constant of about 1.0 X 10(4) M-1 s-1 per copper atom. Under physiological conditions with a low rate of superoxide production, ceruloplasmin preferentially reacts stoichiometrically with the superoxide radical with a rate constant of about 2 X 10(5) M-1 s-1 per copper atom. Under such conditions, the reaction does not result in hydrogen peroxide formation. From the kinetic data obtained it was calculated that in normal human plasma, extracellular-superoxide dismutase will scavenge about twice as much superoxide as ceruloplasmin. Using immobilized antibodies toward extracellular superoxide dismutase and ceruloplasmin, no antigenic cross-reactivity between the two proteins could be detected.

Ceruloplasmin↗

PubMed1999

Is increased redox-active iron in Alzheimer disease a failure of the copper-binding protein ceruloplasmin?

One of the most striking features of Alzheimer disease (AD) is an accumulation of iron in neurofibrillary tangles and senile plaques. Intriguingly, this iron is found as both iron (II) and iron (III) and is redox-active. To address the issue of whether such iron participates in redox cycling, it was essential to investigate how iron (II) accumulates, since oxidation of iron (II) can lead to the generation of reactive oxygen species. To begin to address this issue, here we investigated ceruloplasmin, a key protein involved in the regulation of the redox state of iron by converting iron (II) to iron (III). Cases of AD and age-matched controls, obtained at autopsy with similar postmortem intervals, display similar levels of ceruloplasmin immunoreactivity that is mainly confined to neurons. However, in marked contrast, cases of AD show a significant increase in ceruloplasmin within the neuropil determined by immunoblot analysis of tissue homogenates as well as a generalized increased neuropil staining. Together, these findings suggest that neuronal induction of ceruloplasmin is feeble in AD, even while there is an increase in tissue ceruloplasmin. Therefore, a failure of neuronal ceruloplasmin to respond to iron may be an important factor that then leads to an accumulation of redox-active iron in neurons in AD.

Adult↗