Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.16.3.1 (ceruloplasmin)
5,074 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The reaction of hydrogen peroxide with ox or sheep ceruloplasmin leads to approximately 10% increase of the optical absorption band at 610 nm and of the Type 1 EPR signal. No inactivation or denaturation of the protein is apparent up to 15 H2O2 molar excess. Oxygen is able to restore about 50% of the Type 1 copper absorption in ascorbate-reduced ceruloplasmin, while the other half is recovered after addition of H2O2. It appears that H2O2 undergoes a specific redox reaction with ceruloplasmin, which reveals a fraction of the total copper to be present in the native protein as reduced copper. This fraction is apparently Type 1 copper, while Type 2 is not affected by H2O2.
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PMID:Presence of reduced type 1 copper in ceruloplasmin as revealed by reaction with hydrogen peroxide. 608 18

Proflavine bound-superhelical phi XRFI DNA Molecules undergo single-strand scission upon irradiation with visible light at high fluence rate. As shown by agarose gel electrophoresis analyses, the nicking reaction is (i) oxygen-dependent, (ii) strongly inhibited by catalase and an electron scavenger such as cystamine, and (iii) totally suppressed by ceruloplasmin and radical scavengers such as t-butanol sodium benzoate. This indicates that H2O2, e-, O2 and OH, respectively, are involved in the cleavage process. NaN3, a singlet-oxygen quencher, has very little effect on strand-breakage but it prevents almost completely the alteration of guanine residues (a lesion already observed after irradiation at low fluence rate). Since, in the presence of NaN3, strand scission can occur and guanine (as the other bases) recovered intact, it follows that the radical intermediates produced during breakages are probably not involved in any permanent modification of the DNA bases.
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PMID:Mechanism for strand-break induction in DNA-proflavine complexes exposed to visible light. 645 13

It has been known that there is remarkable antioxidant activity in the human sera, especially those in inflammation and pregnancy. In the present investigation, various sera were examined for the antioxidant activity with the aid of cultured cells. It was recognized that the serum added to the culture medium protected cells from harmful action of active oxygen generated by a hypoxanthine-xanthine oxidase (HX-XO) system. The inflammatory serum has the greatest protective power, followed by pregnant and normal sera in this order. The antioxidant activity of the serum was inversely related to the Fe concentrations. The addition of ceruloplasmin with SOD action could not inhibit the tissue damage, while addition of catalase or hemoglobin with catalase activity could inhibit it. The protective effect was valid against not only HX-XO, but also H2O2. These results show that the chief active oxygen to cause cell damage is H2O2 and the scavenger antioxidants in the serum are hemoglobin and catalase.
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PMID:Protective effect of the serum against cellular damage by active oxygen in culture. 654 44

The concentration of lipoperoxides (estimated as thiobarbituric acid-reactive material) and some components of the antioxidant defence system have been compared in various tissues of lean and congenitally obese mice. NADPH-stimulated lipoperoxide generation in vitro was significantly higher in microsomes (microsomal fractions) prepared from obese hepatic tissue than lean. Plasma, liver and brain lipoperoxide concentration was significantly higher in obese mice. In blood derived from obese mice the concentration of non-enzymic antioxidants including caeruloplasmin and vitamin A was higher, but hepatic retinol concentration was lower in these animals. In all the tissues assayed the glutathione peroxidase activity against H2O2 was less than its activity against cumene hydroperoxide. Assayed with either substrate, glutathione peroxidase activity was significantly higher in the brain and blood of obese mice than their lean counterparts. Conversely, liver glutathione peroxidase was decreased in obese animals, representing 43% of the activity of the lean-mouse liver enzyme against H2O2 and 81% of the cumene hydroperoxide-reducing activity. The liver of obese mice had significantly less, and the kidneys more, oxidized glutathione than the corresponding tissues of lean mice. Further investigations on hepatic tissue indicated that glutathione reductase activity was lower in the obese animals, but there was no significant difference between glucose-6-phosphate dehydrogenase activity in obese and lean mice.
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PMID:Abnormal antioxidant defence in some tissues of congenitally obese mice. 672 63

Oxygen free radicals are probably involved in the pathogenesis of rheumatoid arthritis (RA). The enzymes involved in protection against oxygen free radicals and H2O2 (superoxide dismutase, catalase, and glutathione peroxidase) were measured. Superoxide dismutase was not increased, glutathione peroxidase was slightly and catalase was strongly elevated in RA synovial fluid (SF) compared with control SF. Although these enzymes are present in SF, the activities are insufficient to protect against oxygen free radicals and H2O2. In contrast to transferrin, ferritin was increased in RA synovial fluid. Ceruloplasmin was also elevated. When rat liver microsomes were used as a target for oxygen free radicals, serum and SF were both protective. Gel filtration experiments showed that the fraction pattern in which there was maximal protective potential against lipid peroxidation corresponded closely to the level of ceruloplasmin. After removal of ceruloplasmin from serum or SF, about 70% of the protective capacity disappeared. It is concluded that ceruloplasmin is an important protector against oxygen free radicals.
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PMID:Protective factors against oxygen free radicals and hydrogen peroxide in rheumatoid arthritis synovial fluid. 674 61

Several features of the catalytic oxidation of cysteine by ceruloplasmin and nonenzymic Cu(II) at pH 7 have been compared. The oxidation of cysteine by ceruloplasmin has several properties in common with the Cu(II) catalyzed oxidation of cysteine: pH maxima, thiol specificity, lack of inhibition by anions, and high sensitivity to inhibition by copper complexing reagents. These two catalysts differed in their molecular activity, in their ability to oxidize penicillamine and thioglycolate, and in that H2O2 was produced as a primary product only during Cu(II) oxidation. The oxidation of cysteine by ceruloplasmin was compared also with the ceruloplasmin catalyzed oxidation of o-dianisidine, a classical pH 5.5 substrate. The mechanism of the oxidation of cysteine by ceruloplasmin at pH 7 differed from that of o-dianisidine oxidation because the latter substrate was inhibited by anions but not by copper complexing agents. Spectral and other data suggest that during the ceruloplasmin reaction with cysteine there is a one electron transfer from cysteine to ceruloplasmin resulting in the specific reduction of type 1b Cu(II).
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PMID:Comparison of the catalytic oxidation of cysteine and o-dianisidine by cupric ion and ceruloplasmin. 711 74

We are constantly exposed, throughout life, to a wide variety of extrinsic and intrinsic agents which have the potential to damage cellular biomolecules, including DNA. Imperfections in cellular defence systems which protect against the fixation of DNA damage can lead to an accumulation of mutations which on their own, or in combination with other age-related changes, may contribute to ageing and the development of age-related pathologies. We have previously reported an increase in frequency of mutation with age in human lymphocytes taken from healthy males in the age groups, 35-39, 50-54 and 65-69 years. In this article we report on the findings of a recent study which was designed to assess whether the age-related increase in frequency of mutation was due to a decreased efficacy of the defence systems against ROS-induced DNA damage, namely antioxidant status and DNA repair processes, in the same study subjects. In vivo antioxidant status was assessed in each of the study subjects by measuring blood levels of; superoxide dismutase (SOD; EC 1.15.1.1), glutathione peroxidase (GPx; EC 1.11.1.9), catalase (EC 1.11.1.6), caeruloplasmin (CPL), uric acid and bilirubin. We did not find any statistically significant differences in the mean levels of these antioxidants between the three different age groups. To investigate the efficacy of DNA repair processes against ROS-induced DNA damage, an ELISA was used to quantitate DNA damage (as % single-stranded DNA; %SS-DNA) at various times following treatment of peripheral blood lymphocytes with hydrogen peroxide (H2O2). The results of this part of the study showed that in untreated lymphocytes, basal levels of %SS-DNA were significantly higher in individuals from the 65-69 years age group compared to the 35-39 years age group (p = 0.039, 0.0013; at 5% level of significance). No significant differences were found in H2O2 susceptibility with age immediately following treatment (p = 0.71, 1.00; at 5% level of significance) but a consistent and significant increase was observed in %SS-DNA remaining 90 min post-treatment in lymphocytes from subjects in the 65-69 years age group, compared to %SS-DNA present in lymphocytes from the 35-39 years age group (p = 0.013, 0.024; at 5% level of significance). The results of this study suggest that the age-related increase in frequency of mutations is not contributed to by alterations of in vivo antioxidant status with age but is by a decreased efficacy of the repair of ROS-induced DNA damage with age. The biological implications of somatic mutations in the ageing process are discussed.
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PMID:An investigation of antioxidant status, DNA repair capacity and mutation as a function of age in humans. 756 67

Low density lipoprotein (LDL), if it becomes oxidized, develops several unique properties including the capacity to provoke endothelial cytotoxicity via metal-catalyzed free radical-mediated mechanisms. As were previously have shown that iron-catalyzed oxidant injury to endothelial cells can be attenuated by the addition of exogenous iron chelators such as the lazaroids and deferoxamine, we have examined whether the endogenous iron chelator, ferritin, might provide protection from oxidized LDL. LDL oxidized by iron-containing hemin and H2O2 is toxic to endothelial cells in a time- and dose-dependent fashion. Endothelial cell ferritin content is increased by pretreatment of cells with iron compounds or by the direct addition of exogenous apoferritin; ferritin-loaded cells are markedly resistant to the toxicity caused by oxidized LDL. Iron inactivation by ferritin depends on its ferroxidase activity. When a recombinant human ferritin heavy chain mutant, 222, which is devoid of ferroxidase activity, is added to endothelial cells, unlike the excellent protection afforded by the wild-type recombinant heavy chain, endothelial cells are not protected from oxidized LDL. To assess the in vivo relevance of our observation, we examined human coronary arteries of cardiac explants taken from patients with end-stage atherosclerosis. Large amounts of immunoreactive ferritin are focally detected in atherosclerotic lesions, specifically in the myofibroblasts, macrophages, and endothelium without a notable increase in Prussian blue-detectable iron. These findings suggest that ferritin may modulate vascular cell injury in vivo.
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PMID:Ferritin protects endothelial cells from oxidized low density lipoprotein in vitro. 767 89

The plasma membrane of eukaryotic cells contains an NADH oxidase which can transfer electrons across the membrane. This oxidase is controlled by hormones, growth factors and other ligands which bind to receptors in the plasma membrane. Oncogenes also affect activity of the oxidase. Natural serum components such as diferric transferrin and ceruloplasmin which stimulate proliferation also stimulate membrane oxidase activity. Additional growth factors can be required to complement the proliferative effect. Electron transport across the plasma membrane can be measured by the reduction of impermeable electron acceptors, such as ferricyanide, which also stimulate cell growth. The oxidants activate growth-related signals such as cytosolic alkalinization and calcium mobilization. Antiproliferative agents such as adriamycin and retinoic acid inhibit the plasma membrane electron transport. Flavin, Coenzyme Q and an iron chelate on the cell surface are apparent electron carriers for the transmembrane electron transport. Coenzyme Q10 stimulates cell growth, and Coenzyme Q analogs such as capsaicin and chloroquine reversibly inhibit both growth and transmembrane electron transport. Addition of iron salts to the depleted cells restores activity and growth. The ligand-activated oxidase in the plasma membrane introduces a new basis for control of signal transduction in cells. The redox state of the quinone in the oxidase is proposed to control tyrosine kinase either by generation of H2O2 or redox-induced conformational change.
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PMID:Coenzyme Q10, plasma membrane oxidase and growth control. 775 19

The thiol radioprotector dithiothreitol (DTT) causes biphasic toxicity in V79 cells: exposure to DTT causes loss of clonogenic cell survival at intermediate concentrations of the drug, but is not toxic at lower (< 0.05 mM) or higher (> 2.0 mM) concentrations. Toxicity depends on the medium in which cells are exposed to DTT. Cell killing is less when cells are exposed to DTT in phosphate-buffered saline (PBS) than when in complete, serum-containing medium, and there is no cell killing at any drug concentration when cells are in serum-free medium. When cells are exposed to DTT in PBS containing 10% fetal calf serum (FCS) or 10% dialyzed FCS, cell killing is increased compared to the response in PBS alone, suggesting that some component(s) of serum is involved in DTT toxicity. Addition of micromolar quantities of copper as either free Cu2+ or ceruloplasmin to serum-free medium increases the toxicity of DTT, but addition of free iron or transferrin has no effect. H2O2 is produced during DTT oxidation and appears to be involved in the toxicity of DTT, because toxicity can be prevented by catalase. H2O2 is also toxic to V79 cells in a medium-dependent fashion, but the toxicity is not influenced by addition of copper, ceruloplasmin, iron or transferrin. The rate of DTT oxidation is also medium-dependent and is increased by copper or ceruloplasmin, but not by iron or transferrin. The data are consistent with the hypothesis that the toxicity of DTT is caused by the copper-catalyzed oxidation of DTT, forming H2O2 which, in turn, produces .OH, the ultimate toxic agent, via the Fenton reaction.
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PMID:Role of copper in the oxygen radical-mediated toxicity of the thiol-containing radioprotector dithiothreitol in mammalian cells. 831 32


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