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Sokolov AV, Kostevich VA, Romanico DN, Zakharova ET, Vasilyev VB. Two-stage method for purification of ceruloplasmin based on its interaction with neomycin. BIOCHEMISTRY (MOSCOW) 2012; 77:631-8. [DOI: 10.1134/s0006297912060107] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kirchgessner M, Grassmann E. Untersuchungen zur Kupferverfügbarkeit mit Coeruloplasmin als Testenzym. ACTA ACUST UNITED AC 2009. [DOI: 10.1111/j.1439-0396.1970.tb00161.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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4
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Shokeir MH. Biochemical and immunological characterization of ceruloplasmin genetic variants. A proposed model for quantitative control. Clin Genet 2008; 2:41-9. [PMID: 4106851 DOI: 10.1111/j.1399-0004.1971.tb00254.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Ettle T, Schlegel P, Roth FX. Investigations on iron bioavailability of different sources and supply levels in piglets. J Anim Physiol Anim Nutr (Berl) 2008; 92:35-43. [PMID: 18184378 DOI: 10.1111/j.1439-0396.2007.00707.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two experiments were conducted to investigate the iron bioavailability of different sources and supply levels in piglets. In experiment 1, the influence of feeding an iron deficient basal diet or the basal diet supplemented with 28 ppm Fe either in form of Fe-chelate, crystalline Fe-glycinate, or Fe-sulphate on apparent iron digestibility and on blood parameters was determined. In experiment 2, a dose-response approach was used to determine the effects of supplementing an iron-deficient basal diet with 30, 60, or 90 ppm of Fe either in form of crystalline Fe-glycinate or Fe-sulphate on digestibility of Fe, growth and blood parameters. In experiment 1, comparison of iron sources revealed a tendency (0.05 < p < 0.1) for a higher Fe digestibility from Fe-glycinate (40.9%) compared with Fe-chelate (30.8%) or Fe-sulphate (30.7%). Fe-balance was higher (p < 0.05) for Fe-glycinate compared with Fe-sulphate but iron balance was similar for iron sulphate and iron chelate. Those results, however, were not reflected in data of blood parameters. In experiment 2, iron digestibility, blood parameters and performance were significantly (p < 0.05) influenced by iron supply. Effects of iron source on digestibility of iron were lower than observed in the first experiment.
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Affiliation(s)
- T Ettle
- BOKU, Department of Food Science and Technology, University of Natural Resources and Applied Life Sciences, Vienna, Austria.
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Fee JA. copper proteins systems containing the “Blue” copper center. STRUCTURE AND BONDING 2007. [DOI: 10.1007/bfb0116549] [Citation(s) in RCA: 266] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Malkin R, Malmström BG. The state and function of copper in biological systems. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 33:177-244. [PMID: 4318312 DOI: 10.1002/9780470122785.ch4] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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8
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Inoue K, Akaike T, Miyamoto Y, Okamoto T, Sawa T, Otagiri M, Suzuki S, Yoshimura T, Maeda H. Nitrosothiol formation catalyzed by ceruloplasmin. Implication for cytoprotective mechanism in vivo. J Biol Chem 1999; 274:27069-75. [PMID: 10480920 DOI: 10.1074/jbc.274.38.27069] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ceruloplasmin (CP) is a major multicopper-containing plasma protein that is not only involved in iron metabolism through its ferroxidase activity but also functions as an antioxidant. However, physiological substrates for CP have not been fully identified nor has the role of CP been fully understood. The reaction of nitric oxide (NO) with CP was investigated in view of nitrosothiol (RS-NO) formation. First, formation of heavy metal- or CP-catalyzed RS-NO was examined with physiologically relevant concentrations of NO and various thiol compounds (RSH) such as glutathione (GSH). Among the various heavy metal ions and copper-containing enzymes and proteins examined, only copper ion (Cu(2+)) and CP showed potent RS-NO (S-nitrosoglutathione)-producing activity. Also, RS-NO-forming catalytic activity was evident for CP added exogenously to RAW264 cells expressing inducible NO synthase in culture, but this was not the case for copper ion. Similarly, CP produced endogenously by HepG2 cells showed potent RS-NO-forming activity in the cell culture. One-electron oxidation of NO appears to be operative for RS-NO production via electron transfer from type 1 copper to a cluster of types 2 and 3 copper in CP. Neurological disorders are associated with aceruloplasminemia; besides RS-NO, S-nitrosoglutathione particularly has been shown to have neuroprotective effect against oxidative stress induced by iron overload. Thus, we suggest that CP plays an important catalytic role in RS-NO formation, which may contribute to its potent antioxidant and cytoprotective activities in vivo in mammalian biological systems.
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Affiliation(s)
- K Inoue
- Department of Microbiology, Kumamoto University School of Medicine, Kumamoto 860-0811, Japan
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Affiliation(s)
- Edward I. Solomon
- Department of Chemistry, Stanford University, Stanford, California 94305
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The multicopper-enzyme ascorbate oxidase. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s1062-239x(96)80006-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Hartmann S, Eder K, Kirchgessner M. [Marginal copper and iron requirements of pigs. 1. Effect on hematological parameters, enzyme and copper and iron concentrations in various tissues]. ARCHIV FUR TIERERNAHRUNG 1994; 47:91-106. [PMID: 7668980 DOI: 10.1080/17450399409381798] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The objective of the present study was to investigate physiological effects of a marginal copper and iron supply on pigs. Therefore an experiment was conducted with 4 x 12 growing pigs of the crossbreed Pietrain x Deutsche Landrasse. The animals were fed for a period of 119 days with a diet poor of copper (1.5 mg Cu/kg diet) and/or poor of iron (35 mg Fe/kg diet). Control animals were supplied adequately with copper (4.8 mg Cu/kg diet) and iron (85 mg Fe/kg diet). The diet was given according to weight. After reaching an average weight of 102.6 +/- 3.5 kg the animals were slaughtered. Due to the activity of the coerulplasmin and katalase enzyme and the haematological parameters, the supply of copper and iron could be classified as marginal. There was no interaction between copper deficiency and iron metabolism. The protein metabolism was unchanged. Low copper intake reduced the copper concentrations in serum, liver, muscle and backfat, and low iron intake reduced the iron concentration in serum, liver and muscle. Marginal copper and iron supply had no relevant effect on either food intake and growth performance or carcass characteristics and meat quality.
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Affiliation(s)
- S Hartmann
- Institut für Ernährungsphysiologie, Technischen Universität München-Weihenstephan, Germany
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14
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Jones MM, Wilson DJ, Topping RJ, Laurie SH. The role of rate determining steps in the decorporation of toxic metal ions. Inorganica Chim Acta 1988. [DOI: 10.1016/s0020-1693(00)84946-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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15
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Løvstad RA. Interaction of promazine with human ceruloplasmin. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1987; 19:649-52. [PMID: 3622897 DOI: 10.1016/0020-711x(87)90232-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Promazine is enzymically oxidized by ceruloplasmin without reduction of the 610 nm absorption band of the enzyme. Fluoride inhibited the reaction in a non-competitive manner. The ceruloplasmin oxidase activity is markedly enhanced when promazine is added in the presence of NADH; possibly through a change in enzyme conformation.
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Løvstad RA. Hemin-induced lysis of rat erythrocytes. Protective action of ceruloplasmin and different serum albumins. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1986; 18:171-3. [PMID: 3949060 DOI: 10.1016/0020-711x(86)90151-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Hemin-induced lysis of rat erythrocytes is markedly reduced by ceruloplasmin (human) and serum albumins from different species, the order of effectiveness beings: bovine albumin approximately equal to ceruloplasmin greater than human albumin approximately equal to dog albumin greater than apotransferrin (human). Although the proteins studied had hemin binding capacity, the best protective agents, ceruloplasmin and bovine albumin, did bind hemin less strongly than human and dog albumin. The results suggest the existence of another protective mechanism, possibly involving an interaction between erythrocyte membranes and serum proteins.
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Løvstad RA. Iron ion induced haemolysis: effect of caeruloplasmin, albumin and ascorbate (vitamin C). THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1983; 15:1067-71. [PMID: 6617951 DOI: 10.1016/0020-711x(83)90044-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Human caeruloplasmin (ferroxidase), bovine serum albumin and ascorbate protected washed rat erythrocytes against iron ion stimulated haemolysis, while superoxide dismutase, catalase and other scavengers of "activated oxygen" species had little or no effect. Caeruloplasmin retained its protective action when its oxidase activity was completely inhibited by azide, and when its copper ions had been removed. The effect of caeruloplasmin, apocaeruloplasmin and albumin could not be attributed to a binding of iron ions to protein molecules.
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Løvstad RA. The protective action of ceruloplasmin on copper ion stimulated lysis of rat erythrocytes. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1982; 14:585-9. [PMID: 7106358 DOI: 10.1016/0020-711x(82)90041-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
1. Human ceruloplasmin effectively protects washed rat erythrocytes against copper ion stimulated lysis. 2. Experiments suggest that the protective action is not associated with (a) the oxidase activity of ceruloplasmin, (b) the protein's superoxide radical scavenging ability, (c) its ability to weakly bind cupric ions (nonspecific binding) or (d) ceruloplasmin bound sialic acid.
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Gutteridge JM, Stocks J. Caeruloplasmin: physiological and pathological perspectives. Crit Rev Clin Lab Sci 1981; 14:257-329. [PMID: 7023838 DOI: 10.3109/10408368109105866] [Citation(s) in RCA: 176] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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20
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Sheline RR, Strothkamp KG. The pH dependence of the inhibition of ascorbate oxidase by anions. Biochem Biophys Res Commun 1980; 96:1343-8. [PMID: 7437074 DOI: 10.1016/0006-291x(80)90098-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Herve M, Garnier A, Tosi L, Steinbuch M. Ceruloplasmin-anion interaction. A circular dichroism spectroscopic study. BIOCHIMICA ET BIOPHYSICA ACTA 1976; 439:432-41. [PMID: 8118 DOI: 10.1016/0005-2795(76)90080-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The effect of anion binding to ceruloplasmin has been studied using absorption and cirbular dichroism spectral data. At anion to ceruloplasmin molar ratios approaching infinite, OCN-, N3- and SCN- bind to ceruloplasmin giving rise to similar alterations in circular dichroism and absorption spectra. The positive bands at 610 and 520 nm in circular dichroism spectra disappear, a negative one apperars at 600 nm and the peak at 450 nm is only slightly modified. There is a new negative band at 410 nm well-defined in OCN- ceruloplasmin spectra. The decrease in absorption at 610 nm is ascribed to the disruption of one type I Cu-S(cysteine) bond owing presumably to the changes induced by anions in the protein secondary structure. The new band at 410 nm is assigned to a charge transfer transition from the ligand replacing cysteine at its binding site. Both absorption and circular dichroism spectra show isobestic points indicating that anion binding to the enzyme, disruption of one of the two type I Cu-S bonds and coordination of this Cu to another protein residue take place simultaneously.
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Herve M, Garnier A, Tosi L, Steinbuch M. The effects of neutral salts on the conformational transition of ceruloplasmin. BIOCHIMICA ET BIOPHYSICA ACTA 1975; 405:318-23. [PMID: 1180958 DOI: 10.1016/0005-2795(75)90097-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Johnson RA, Pilkis SJ, Hamet P. Liver membrane adenylate cyclase. Synergistic effects of anions on fluoride, glucagon, and guanyl nucleotide stimulation. J Biol Chem 1975. [DOI: 10.1016/s0021-9258(19)41108-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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25
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Tosi L, Garnier A, Herve M, Steinbuch M. Ceruloplasmin-anicn interaction. A resonance Raman spectroscopic study. Biochem Biophys Res Commun 1975; 65:100-6. [PMID: 167763 DOI: 10.1016/s0006-291x(75)80066-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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26
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Gunnarsson PO, Nylén U, Pettersson G. Kinetics of the interaction between ceruloplasmin and reducing substrates. EUROPEAN JOURNAL OF BIOCHEMISTRY 1973; 37:41-6. [PMID: 4729428 DOI: 10.1111/j.1432-1033.1973.tb02954.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Byers W, Curzon G, Garbett K, Speyer BE, Young SN, Williams RJ. Anion-binding and the state of copper in caeruloplasmin. BIOCHIMICA ET BIOPHYSICA ACTA 1973; 310:38-50. [PMID: 4351064 DOI: 10.1016/0005-2795(73)90006-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Young SN, Curzon G. A method for obtaining linear reciprocal plots with caeruloplasmin and its application in a study of the kinetic parameters of caeruloplasmin substrates. Biochem J 1972; 129:273-83. [PMID: 4643313 PMCID: PMC1174077 DOI: 10.1042/bj1290273] [Citation(s) in RCA: 49] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
1. The curved plots of 1/v against 1/[S] obtained when caeruloplasmin oxidizes NN-dimethyl-p-phenylenediamine were investigated. The first free-radical oxidation product of caeruloplasmin oxidation of NN-dimethyl-p-phenylenediamine is required for curvature, as straight-line plots were obtained when activities were measured either before appreciable free-radical product had appeared or in the presence of ascorbate, which reduced it back to NN-dimethyl-p-phenylenediamine. 2. In the presence of ascorbate linear reciprocal-plots were obtained with all of the 37 substrates tested. V(max.) values varied over only an eightfold range and those for the 20 p-amino compounds over only a twofold range. K(m) values, however, varied over a 10(4)-fold range. The small range of V(max.) values indicates that the rate-limiting step in caeruloplasmin action is relatively independent of the nature of the substrate. K(m) values suggest that substrates bind primarily by ring electrons, although certain side-chain groups increased the K(m) in a manner unrelated to likely changes of ring-electron densities. A mechanism involving repulsion between negative charges on the substrate and the enzyme was supported by the variation of the K(m) of 5-hydroxyindol-3-ylacetic acid with pH.
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Gunnarsson PO, Nylén U, Petersson G. Inhibition of ceruloplasmin by inorganic anions. EUROPEAN JOURNAL OF BIOCHEMISTRY 1972; 27:572-7. [PMID: 5050664 DOI: 10.1111/j.1432-1033.1972.tb01874.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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30
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Gunnarsson PO, Petersson G. Inhibition of ceruloplasmin by unsaturated and aromatic carboxylic acids. EUROPEAN JOURNAL OF BIOCHEMISTRY 1972; 27:564-71. [PMID: 5050663 DOI: 10.1111/j.1432-1033.1972.tb01873.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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31
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Curzon G, Young SN. The ascorbate oxidase activity of caeruloplasmin. BIOCHIMICA ET BIOPHYSICA ACTA 1972; 268:41-8. [PMID: 4622934 DOI: 10.1016/0005-2744(72)90195-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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32
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Imoto T, Akasaka K, Hatano H. Nuclear magnetic resonance studies on the interaction between salicylate and ceruloplasmin. FEBS Lett 1971; 15:149-152. [PMID: 11945834 DOI: 10.1016/0014-5793(71)80044-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- T Imoto
- Department of Chemistry, Faculty of Science, Kyoto University, Kyoto, Japan
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Mondorf AW, Mackenrodt G, Halberstadt E. [Ceruloplasmin. I. Biochemistry of ceruloplasmin. II. Influence of estrogens on the ceruloplasmin content of the serum]. KLINISCHE WOCHENSCHRIFT 1971; 49:61-70. [PMID: 5543067 DOI: 10.1007/bf01497302] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Gunnarsson PO, Pettersson G, Pettersson I. pH-dependence of the ceruloplasmin catalyzed oxidation of dimethyl-p-phenylenediamine. EUROPEAN JOURNAL OF BIOCHEMISTRY 1970; 17:586-92. [PMID: 5493987 DOI: 10.1111/j.1432-1033.1970.tb01204.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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36
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Andréasson LE, Vänngård T. Evidence of a specific copper(II) in human ceruloplasmin as a binding site for inhibitory anions. BIOCHIMICA ET BIOPHYSICA ACTA 1970; 200:247-57. [PMID: 4313536 DOI: 10.1016/0005-2795(70)90168-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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37
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Influence of chloride ions on the interaction of hydroquinone with copper ions under anaerobic conditions. Russ Chem Bull 1970. [DOI: 10.1007/bf00853365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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38
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Curzon G, Speyer BE. The effects of inhibitor mixtures and the specific effects of different anions on the oxidase activity of caeruloplasmin. Biochem J 1968; 109:25-34. [PMID: 5669845 PMCID: PMC1186748 DOI: 10.1042/bj1090025] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
1. The interpretation of the effects of mixtures of inhibitors on enzymes is considered. 2. The effects of inhibitor mixtures on caeruloplasmin were determined. 3. Fluoride, chloride and cyanate inhibit at one type of site (alpha), whereas bromide and iodide inhibit at another type (beta) present in the same enzyme intermediate. 4. Effects of inhibitor mixtures containing azide or cyanide are consistent with previous indications (Speyer & Curzon, 1968) that these ligands form inhibited complexes with different enzyme intermediates. 5. Isobols of halides or of cyanate with azide indicate that azide inhibits caeruloplasmin by bridging two alpha sites, these being reduced copper atoms. 6. Iodide and cyanate give hyperbolic plots of 1/v against [I]. 7. It is suggested that in the cyanate-inhibited complex the inhibitor binds to a reduced copper atom (alpha site) but that binding of cyanate at another copper atom is sterically prevented. It is suggested that the less bulky alpha-site inhibitors, fluoride and chloride, cause complete inhibition by binding to both of these copper atoms, which can also be bridged by a single azide group. 8. Each halide shows a pattern of effects on caeruloplasmin that is qualitatively distinct from that of other halides.
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Abstract
1. The reversible inhibition of the oxidase activity of caeruloplasmin by cyanide was investigated. 2. The kinetics are unusual, being competitive but with the inhibited complex formed only during cycling. 3. Inhibitory concentrations of cyanide are comparable with that of caeruloplasmin. 4. One azide group completely inhibits a caeruloplasmin molecule but two cyanide groups are required. 5. The results suggest that azide binds to a half-reduced or fully reduced conformational isomer of the enzyme whereas cyanide binds to completely reoxidized isomers, and that inhibited complexes contain ligand bridges between copper atoms.
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