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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 157 (1992), S. 411-416 
    ISSN: 1432-072X
    Keywords: Urease ; Sporosarcina ureae ; Nickel ; Alkaline stable ; Enzyme activation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Alkaline stable (pH 7.75–12.5) urease from Sporosarcina ureae was purified over 400-fold by ion exchange and hydrophobic interaction chromatography. The cytoplasmic enzyme was remarkably active with a specific activity of greater than 9300 μmol urea degraded min-1 mg protein-1 at pH 7.5, where it has optimal activity. Although S. ureae is closely related to Bacillus pasteurii, known to posses a homopolymeric urease containing 1 nickel per subunit [M r=65000], the S. ureae enzyme is comprised of three subunits [apparent M r=63100 (α), 14500 (β), and 8500 (γ)] in an estimated ∝βγ stoichiometry and contains 2.1±0.6 nickel ions per ∝βγ unit as measured by atomic absorption spectrometry. Stationary phase cultures sometimes possessed low levels of urease activity, but the specific activity of cell extracts of partially purified urease preparations from such cultures could be elevated by heat treatment, dilution, or dialysis to values comparable to those observed in samples from exponentially grown cells.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature structural biology 10 (2003), S. 234-236 
    ISSN: 1072-8368
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] Several Ni-containing enzymes are intimately associated with carbon monoxide (CO), a toxic gas. For example, CO is generated by the Ni bound form of acireductone dioxygenase, an enzyme acting in the methionine salvage pathway. In addition, the diatomic molecule is both an essential metallocenter ...
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Biochemistry 23 (1984), S. 801-804 
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Biochemistry 24 (1985), S. 1629-1633 
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Inorganic chemistry 32 (1993), S. 634-638 
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 106 (1984), S. 3062-3064 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 48 (1987), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract During oxidative stress, Methanobacterium thermoautotrophicum derivatizes the two-electron carrier, coenzyme F420, to form factor 390 (F390). Two methods were used to estimate the reduction potential of this chromophore. Oxidative titration of reduced F390 by potassium ferricyanide in the presence of either NADH or a redox indicator dye yielded an estimate of −320 mV for the reduction potential. A sulfite dissociation constant of 11 mM was measured which correlates to a reduction potential of −310 mV when compared to other 5-deazaflavins and nicotinamides. Thus, the F390 reduction potential is within a useful working range for the microorganism.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology reviews 27 (2003), S. 0 
    ISSN: 1574-6976
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Nickel is an essential nutrient for selected microorganisms where it participates in a variety of cellular processes. Many microbes are capable of sensing cellular nickel ion concentrations and taking up this nutrient via nickel-specific permeases or ATP-binding cassette-type transport systems. The metal ion is specifically incorporated into nickel-dependent enzymes, often via complex assembly processes requiring accessory proteins and additional non-protein components, in some cases accompanied by nucleotide triphosphate hydrolysis. To date, nine nickel-containing enzymes are known: urease, NiFe–hydrogenase, carbon monoxide dehydrogenase, acetyl–CoA decarbonylase/synthase, methyl coenzyme M reductase, certain superoxide dismutases, some glyoxylases, aci-reductone dioxygenase, and methylenediurease. Seven of these enzymes have been structurally characterized, revealing distinct metallocenter environments in each case.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    [s.l.] : Macmillian Magazines Ltd.
    Nature 419 (2002), S. 174-178 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Methylating agents generate cytotoxic and mutagenic DNA damage. Cells use 3-methyladenine-DNA glycosylases to excise some methylated bases from DNA, and suicidal O6-methylguanine-DNA methyltransferases to transfer alkyl groups from other lesions onto a cysteine residue. Here we ...
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    JBIC 2 (1997), S. 279-286 
    ISSN: 1432-1327
    Keywords: Key words Nickel enzymes ; Metal Transport ; Metallochaperone ; Metal shuttle ; Accessory protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract  The five known nickel-dependent enzymes include urease, hydrogenase, carbon monoxide dehydrogenase (and CO dehydrogenase/acetyl-coenzyme A synthase), methyl-S–coenzyme M reductase, and one class of superoxide dismutase. Consistent with their disparate functions, these Ni enzymes have distinct metallocenter structures that vary in Ni coordination geometry, number and types of metals, and the presence of additional components. Sophisticated cellular Ni processing systems have been devised to allow for specific and functional incorporation of Ni into these proteins. This review highlights several themes that are common to the enzyme activation processes and summarizes current concepts related to the enzyme-specific Ni assembly pathways.
    Type of Medium: Electronic Resource
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