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:1.9.3.1 (cytochrome oxidase)
8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Binuclear cupric ion clusters have been established in: human ceruloplasmin, hemocyanin, and mushroom tyrosinase. Substantial evidence makes it very probable that fungal laccase and zucchini ascorbate oxidase contain this cluster. Some evidence makes it possible that copper clusters function in the catalytic cycles of cytochrome oxidase (mammalian) and dopamine-beta-hydroxylase. These studies throw light on the criteria which must be employed to establish the existence of functional binuclear copper clusters in enzymes: (1) Stoichiometric Criteria: binding of O2 and CO with Cu/ligand = 2; redox titrations with n = 2; (2) Physical and Chemical Criteria: magnetic evidence of diminished paramagnetism of cupric centers, EPR evidence of broadened or absent absorptions, EPR evidence of magnetic dipolar interactions among cupric ions; absorption bands characteristic of Cu(II)-Cu(II) complexes; laser resonance raman scattering characteristic of peroxidic dioxygen in the oxyforms.
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PMID:Binuclear copper clusters as active sites for oxidases. 18 78

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.
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PMID:Ceruloplasmin: the copper transport protein with essential oxidase activity. 77 38

Evidence for the presence of the plasma protein, ceruloplasmin, in heart and other tissues of the rat was sought using various techniques. With p-phenylenediamine, ceruloplasmin-like oxidase activity was detected in heart post-mitochondrial and 100 000 X g supernatants in amounts far exceeding those that could be accounted for by residual blood. Much lower levels were detected in kidney, brain and liver. Oxidase activity of heart purified on DEAE-cellulose in the same way as rat plasma ceruloplasmin and behaved identically also in disc gel electrophoresis. The presence of ceruloplasmin in heart extracts was confirmed immunologically by Ouchterlony diffusion, using rabbit antibody raised against pure rat ceruloplasmin. When pure [3H]leucine-labeled ceruloplasmin was infused intravenously into a copper-deficient rat, radioactivity was concentrated in the heart and brain within 2 h; radioactive counts per g attained 11 and 3 times those of plasma in the two organs, respectively. A lesser concentration occurred in the liver. the results suggest that circulating ceruloplasmin (made by the liver) finds its way into the cells of some organs, especially the heart, a phenomenon which may be related to the function of ceruloplasmin to provide copper to the cytochrome oxidase of various tissues.
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PMID:Plasma ceruloplasmin. Evidence for its presence in and uptake by heart and other organs of the rat. 91 89

Healthy, free-living men and women aged 20-83 y (n = 127) were studied to determine the effects of age and sex on copper absorption, biological half-life (BH), and status. Copper absorption was greater in women (71%) than in men (64%) aged 20-59 y (P = 0.02), but did not differ in men and women aged 60-83 y. BH of 67Cu ranged from 13 to 33 d and differed between men and women aged 20-59 y (P = 0.006), but not between men and women aged 60-83 y. Plasma copper, enzymatic ceruloplasmin (Cp), and immunoreactive (RID) Cp were significantly higher in women than in men (P < 0.005), but superoxide dismutase (SOD) and in vitro 67Cu uptake by red blood cells did not differ. Plasma copper, RID Cp, and cytochrome oxidase in platelets and mononuclear cells were significantly affected by age (P < 0.005). Oral contraceptives elevated plasma copper, enzymatic Cp, and SOD activity but not copper absorption and BH in women aged 20-39 y. Copper intake from self-selected diets was 0.9-1.2 mg/d for women and 1.2-1.3 mg/d for men, but net copper absorption (micrograms Cu.kg body wt-1.d-1) did not differ. Thus, dietary copper intake requirements may differ between men and women.
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PMID:Effects of age and sex on copper absorption, biological half-life, and status in humans. 132 83

The aim of this article is to emphasize the important role that copper plays in the function of nerve cells. We are reporting preliminary data which suggest that the swelling of axons which we produce in rats by iminodipropionitrile, IDPN, is due to its chelating action on copper, and how conversely supplementation with copper abolishes both symptoms and lesions. The copper values we obtained by atomic absorption spectrophotometry of the spinal cord and brain from the animals fully support this contention. In comparing these results with the diseases that are known to be due to copper deficiency, namely Menkes disease in man, swayback in lambs and several neurological mutant mice, we find not only similar axonal swellings, but also amelioration of symptoms and lesions by early administration of copper. Considering the main forms in which copper is present, we discuss the cuproproteins, i.e. ceruloplasmin and metallothionein, and their role in transport and delivery of copper to various organs. Further, the many cuproenzymes i.e. superoxide dismutase, tryptophan-2,3-dioxygenase, lysine oxidase, cytochrome oxidase, monoamine oxidases, tyrosinase, dopamine-beta-hydroxylase and d-amino levulinate dehydratase are noted for their roles in the nervous system. Finally, we suggest that neuronal copper deficiency should be more fully investigated as a possible etiological factor in the more common neurodegenerative diseases, such as Alzheimer's disease and amyotrophic lateral sclerosis, ALS.
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PMID:Deficiency of copper can cause neuronal degeneration. 161 61

Zinc sulfate-enriched lactic acid lactobacterin was used in the combined treatment of 23 children with celiac disease, aged from 1 to 10 years. A group of 23 children with celiac disease who received lactic acid lactobacterin without zinc were used as control. The patients treated with lactobacterin containing zinc showed a higher increase in body mass, total protein and zinc levels in the blood serum and elevated activity of metalloenzymes-ceruloplasmin and cytochrome oxidase.
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PMID:[The efficacy of the use of lactic acid lactobacterin enriched with zinc in the treatment of patients with celiac disease]. 179 43

The structural comparison of copper-containing proteins has provided a new dimension to the relationships suggested by sequence similarities. Ryden (1988) summarized the putative relationships, suggesting that a primordial single-domain cupredoxin evolved into the multidomain copper oxidases. The structures have revealed the fact that the differences reside primarily in insertions and deletions at junctions between secondary-structure elements. The mechanism of evolution (e.g., integration of new sequences into regions not essential to the Greek key fold) remains unknown. Which of the properties of a cupredoxin fold are necessary for function is the subject of site-directed mutagenesis studies. Can two of the ligands be interchanged (e.g., the upstream histidine and partially answered by the multidomain copper oxidase structure. The Tyr-Cys-Thr sequence in plastocyanin (in which threonine is a member of the hydrogen-bonding pair) is homologous with the His-Cys-His sequence in ascorbate oxidase. In the latter electron transfer is believed to flow from the type I copper (bound by the cysteine) to the trinuclear cluster, probably via these histidine residues. Hence, one might infer that the tyrosine and threonine have some role in electron transfer. Tyr-83 has been previously implicated in NMR studies as a primary site of electron transfer. The multi-copper protein structures have revealed interesting new features. The extra coppers are bound at domain interfaces, and can be single metals or the novel trinuclear cluster, depending on the availability of liganding histidines. A structural model of ceruloplasmin suggests that it will have at least two type I sites and, possibly, a third type I site such as stellacyanin (no methionine ligand), as well as a binding site for a trinuclear cluster. The similarity of the sequences of N2O reductases and a domain of cytochrome oxidase to the sequences of proteins with known structures suggests that these, too, will have Greek key domains. Galactose oxidase and hemocyanin do not have Greek key folds in their functional domains, although each does have a Greek key domain. The need for a Greek key fold remains obscure. The apoproteins are clearly stable without metals; there are examples other than immunoglobulins of Greek key folds. So far copper seems to be found in a very limited subset of structures; other chapters in this volume show that zinc, for example, has a much wider variety of environments in proteins, as does iron. It may be that the copper-containing Greek key proteins represent a very small evolutionary niche.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Copper protein structures. 179 5

Weanling albino male mice rapidly develop biochemical signs of copper deficiency when fed a purified diet containing 0.5 mg Cu/kg. Plasma ceruloplasmin activity of copper-deficient (-Cu) mice was 5% of that of copper-adequate (+Cu) control mice after only 3 d on the diet. More gradual loss of organ (liver, spleen, and thymus) cytochrome c oxidase activity was observed during the next 4 wk. Body weight was equivalent between +Cu and -Cu mice, but thymus weight dropped faster in -Cu mice than +Cu mice. The number of antibody producing cells to sheep erythrocytes was lower in -Cu mice compared to +Cu mice after 17 d on the diet. Spleen cytochrome oxidase activity of -Cu mice was 50% of that of +Cu mice by 10 d on the diet. Mitogenic response of splenic and thymic lymphocytes to concanavalin A (con A) was not greatly different between +Cu and -Cu mice. Splenocytes from -Cu mice had a 3-fold higher thymidine incorporation rate in the absence of mitogen compared to +Cu mice. The depressed antibody and high mitogenic background responses of -Cu mice were similar to previous work with another strain (C58) of mice that had been started on copper-deficient treatment from birth. However, the normal proliferative response to con A stimulation in postweaning copper deficiency differs from the previous model. Mice of both studies were very copper-deficient as judged by liver copper levels. Timing of the copper-deficient treatment influences the manner in which copper deficiency alters the immune response.
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PMID:Biochemical and immunological changes in mice following postweaning copper deficiency. 248 23

The complexes of NO with CuB of cytochrome c oxidase in which cytochrome a3 may or may not be ligated to cyanide or fluoride are photodissociable. NO does not appear to react with CuB in complexes of cytochrome c oxidase in which sulphide or mercaptans are ligated to the haem iron of cytochrome a3. A comparison is made between the photoreactivity of the complexes of NO with cytochrome c oxidase and those with ceruloplasmin, ascorbate oxidase, and haemocyanin. It is shown that the photoreactivity of CuB 2+.NO in cytochrome c oxidase is not unique for this enzyme, but may also be observed in the complexes of NO with type-1 copper-containing enzymes. This would suggest that the ligation of CuB in cytochrome c oxidase shows some similarity to type-1 copper in blue oxidases.
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PMID:The photoreactivity of the copper-NO complexes in cytochrome c oxidase and in other copper-containing proteins. 299 61

Chicks were fed on diets containing either no added vitamin A or 3300 micrograms/kg or 330,000 micrograms/kg retinol equivalents for 30 d. Concentrations of copper, iron and zinc were higher in liver and lower in plasma at low and high intakes of vitamin A. Haemoglobin, packed cell volume and erythrocyte levels were depressed by both low and high vitamin A intake and could be related to vitamin A levels by quadratic equations. The Zn and Fe levels in erythrocytes and serum albumin and ceruloplasmin were also affected in a similar fashion by low or high vitamin A diets. Hepatic activity of alcohol dehydrogenase (EC 1.1.1.1) and cytochrome oxidase (EC 1.9.3.1) paralleled Zn and Cu concentrations respectively. Superoxide dismutase (EC 1.15.1.1) and hydrolysis of triolein and retinyl palmitate were not correlated significantly with concentrations of metals but were correlated negatively with log vitamin A concentration. No changes in bone concentrations of Cu, Fe or Zn were detected. It is suggest that vitamin A influences metabolism of Cu, Fe and Zn possibly, in part, due to a decrease in secretion of transport proteins by the liver.
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PMID:The effect of different dietary levels of vitamin A on metabolism of copper iron and zinc in the chick. 303 14


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