Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.01 seconds)

(1) 45% of the total copper of green zucchini ascorbate oxidase is EPR-detectable. At least two species of copper are present, one with a small A parallel (Type 1) and one with a large A parallel (Type 2). Computer simulated spectra indicated 50% contribution by each type of copper. (2) Azide inhibited ascorbate oxidase activity by an uncompetitive mechanism. EPR and optical spectra performed on titration of ascorbate oxidase with azide indicated the formation of a copper-azide complex. The Type 2 copper appears to be the binding site of azide. The involvement of the EPR non-detectable copper as an anion binding site with high affinity toward azide can not be excluded.
Mol Cell Biochem 1975 May 30
PMID:The effect of azide on the spectral and catalytic properties of ascorbate oxidase. 16 78

Cytochrome c oxidase from the inner membrane of yeast mitochondria consists of seven nonidentical protein subunits, three being synthesized on mitochondrial ribosomes (molecular weights I: 43 K, II: 34 K, and III: 24 K) and four being made on cytoplasmic ribosomes (molecular weights IV: 14 K, V: 12 K, VI: 12 K, and VII: 4.5 K). In the present study all four cytoplasmically synthesized subunits of the enzyme were isolated on a large scale using ion exchange chromatography and gel filtration. Their amino acid composition as well as their amino- and carbosy-terminal amino acid residues have been determined. Sequence determinations of subunits IV and VI are already in an advanced state. The sequence of subunit VI is characterized by a large amino-terminal stretch dominated by charged amino acid residues followed by a cluster of hydrophobic amino acids. The binding site of yeast cytochrome oxidase for cytochrome c was studied by chemical crosslinking experiments. The formation of a disulfide bridge between the two proteins was observed by using cytochrome c from yeast modified with 5-thionitrobenzoate at the cysteinyl residue in position 107. Alternatively, a disulfide between yeast cytochrome c and the oxidase could be formed directly by oxidation with copper phenanthroline. Gel electrophoresis of the crosslinked complexes in sodium dodecyl sulfate revealed a new protein band with an apparent molecular weight of 38 K. This new band appears to be derived from cytochrome c and from subunit III of cytochrome oxidase.
Mol Cell Biochem 1977 Feb 04
PMID:Structure of cytochrome c oxidase from baker's yeast - a progress report. Preparation of four subunits for amino acid sequence determination and attempts to localize the cytochrome c binding site. 19 98

1. Human gastrointestinal secretions formed soluble copper complexes when labelled in vitro with 64Cu. 2. Copper-binding substances of low molecular weight were demonstrated in the saliva, gastric juice and secretin-stimulated duodenal aspirate of nomal subjects by dialysis and gel-chromatography studies. 3. The nature of the copper complexes formed by secretions obtained from patients with Wilson's disease was similar to that oc complexes formed by secretions of normal subjects. 4. Bile contained a copper-binding fraction of high molecular weight which was more concentrated in gall-bladder than hepatic bile. Between pH 5 and pH 8, this component had a greater binding affinity EDTA at a concentration of 10 mmol/1. 5. Absorption of 64Cu from 64Cu-labelled saliva, gastric juice or L-histidine solution (100 mmol/1) administered intraduodenally into groups of rats was similar to that observed in a control series given [Cu]cupric acetate in sodium chloride solution. In contrast, the absorption of 64Cu from labelled hepatic and gall-bladder bile was significantly reduced. 6. The results suggest that dietary copper forms soluble complexes with the alimentary secretions and that these complexes influence absorption of the metal according to their molecular size. The net uptake of ingested copper from the gut lumen ms, low-molecular-weight ligands in the alimentary secretions and a macromolecular copper-binding complex of bile.
Clin Sci Mol Med 1975 Sep
PMID:Studies on the nature of complexes formed by copper with human alimentary secretions and their influence on copper absorption in the rat. 24 May 30

The effect of the exchangeable cation on the condensation of glycine and alanine was investigated using a series of homoinic bentonites. A cycling procedure of drying, warming and wetting was employed. Peptide bond formation was observed, and the effectiveness of metal ions to catalyze the condensation was Cu2+ greater than Ni2+ approximately Zn2+ greater than Na+. Glycine showed 6% of the monomer incorporated into oligomers with the largest detected being the pentamer. Alanine showed less peptide bond formation (a maximum of 2%) and only the dimer was observed.
J Mol Evol 1979 Nov
PMID:The role of metal ions in chemical evolution: polymerization of alanine and glycine in a cation-exchanged clay environment. 51 39

1. Two different molecular forms of dopamine-beta-hydroxylase were isolated from human serum; a major component (Peak I enzyme) with a molecular weight of 368000 and with a higher specific activity and a minor component (Peak II enzyme) with a molecular weight of 188000 and with a lower specific activity. 2. Both forms require ascorbic acid for the activity, and are stimulated by fumarate. Addition of N-ethylmaleimide or copper also increased the activity. The optimal pH of both forms in the presence of 20mM tyramine as substrate is 5.0. 3. Km values toward tyramine of Peak I enzyme and Peak II enzyme were 1.67 mM and 14.2 mM respectively. 4. Both Peak I enzyme and Peak II enzyme are glycoprotein.
Mol Cell Biochem 1977 Dec 29
PMID:Purification and properties of human serum dopamine-beta-hydroxylase. 56 50

The particles of an iron hydroxide sol were found to be a suitable model for protein-oxidizing enzymes such as peroxidase and polyphenol oxidase. In addition to small molecules such as pyrogallol, human serum proteins, albumin and gamma-globulin, are shown to be substrates of the oxidizing model. The activity is markedly increased by the addition of small amounts of copper to the iron in the particles of the sol. The size and molecular weight of the enzyme model, as well as the number of active centers were determined.
Mol Biol Rep 1978 Jun 16
PMID:Iron hydroxide: model for enzymes that oxidize proteins. 68 84

Using the thermal denaturation method the effect of bivalent copper of (4-10(-6)-10(-3)) M concentrations on the helix-coil transition of DNA was studied in the solution of Na+ concentrations 10(-3)-10(-1) M. Unlike the previous studies, this paper makes allowance for the effect of impurity ions present in DNA and deionized water. It has been shown that in the region of low Cu2+ and Na+ concentrations, thermal stability increases, the melting range extends and the denaturation curves become asymmetric. At concentrations more than approximately 3-10(-5) M Cu2+, melting temperature starts to fall, and the range reduces to 1-1.5 degrees at [Cu2+] greater than or equal to 2-10(-4) M. As [Cu2+] reaches these values, the denaturation curve asymmetry and melting range increase again, which is due to the inversion of the relative stability of AT- and GC-pairs. Employing experimental and phase-transition-theory data for homopolymers, the constants of Cu2+ binding with phosphates and DNA bases were calculated. The concentration dependence of the DNA denaturation parameters was shown to be governed by the superposition of binding Cu2+ with phosphates and nucleic acid bases.
Mol Biol (Mosk)
PMID:[Effect of divalent copper ions on heat denaturation of DNA]. 68 90

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

1. A screening procedure is described to assess rapidly the clinical potential of chelating agents for the treatment of Wilson's disease. 2. Rats were used as the test animal; they were kept in metabolic cages and the urine was collected in copper-free containers. The compounds investigated were given by mouth as a standard dose of 100 mg. Copper was determined by atomic absorption spectrophotometry. 3. Basal urine copper excretion was 65-1 +/- SE 2-93 nmol/24 h (4-1 microgram +/- 0-185). After penicillamine this rose to 367-1 nmol and after trien to 305-9 nmol. 4. Certain compounds caused a reduction in the amount of copper excreted in the urine, probably by forming insoluble chelates with the metal, hence rendering it unavailable for excretion at the glomerulus.
Clin Sci Mol Med 1977 Oct
PMID:The effect of certain chelating compounds on the urinary excretion of copper by the rat: observations on their clinical significance. 91 55

1. A study has been made of peptide excretion in twenty cases of Wilson's disease, ligand-exchange column chromatography being used to separate peptides from free amino acids. Previous reports of excess of peptide output in the disease were confirmed and the excess was shown to be highly significant statistically. 2. A considerable fraction of the excess of peptide output was shown to consist of hydroxyproline-containing peptides derived from collagen degradation. 3. The method of rank correlation showed that the difference both in free amino acid and peptide-bound amino acid output in cases of Wilson's disease and in control subjects was mainly quantitative; the pattern of amino acid excretion was qualitatively similar in both groups. 4. Evidence is presented that the increase copper output in the urine in the disease is not secondary to peptiduria.
Clin Sci Mol Med 1976 Oct
PMID:Urinary excretion of peptides and of hydroxyproline in Wilson's disease. 97 77


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