ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Tri- and tetramethylhydroquinone as electron donors for ammonia monooxygenase in whole cells of Nitrosomonas europaea (1986)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 33 (1986), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Ten redox reagents have been tested as electron donors to ammonia monooxygenase in whole cells of Nitrosomonas europaea. Positive results were obtained with tri- and tetramethylhydroquinone. An earlier study showed that phenol was converted into hydroquinone by the monooxygenase. Cells were therefore incubated with trimethylphenol, to see if its hydroxylation to trimethylhydroquinone would lead to a self-sufficient conversion of trimethylphenol into trimethylquinone. No trimethylquinone could be detected. The maximal rates of propene epoxidation obtained with tri-and tetramethylhydroquinone were 1.8 and 4.6 μmol · h−1· mg protein−1, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1986.tb01287.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Kinetic and antigenic similarities for cellobiose dehydrogenase from the brown rot fungus Coniophora puteana and the white rot fungus Phanerochaete chrysosporium (1996)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 145 (1996), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Cellobiose dehydrogenase was purified from the brown rot fungus Coniophora puteana. Strong cross-reaction was observed with antibodies to cellobiose:quinone oxidoreductase from the white rot fungus Phanerochaete chrysosporium. Kinetic measurements were made with cellobiose as electron donor. Ferricyanide and DCPIP both showed a pH optimum close to pH 4, but activity with ferricyanide declined more rapidly when the pH was raised. Dioxygen reduction to hydrogen peroxide was observed, but at a much lower rate than for other acceptors. These properties are similar to those of cellobiose dehydrogenase from P. chrysosporium, despite differences between brown and white rot modes of decay.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1996.tb08613.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Pathways for production of Fenton's reagent by wood-rotting fungi (1994)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology reviews 13 (1994), S. 0 
    Details
    ISSN: 1574-6976
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract: Many forms of Fe(II) react with H202 to generate hydroxyl radicals (Fenton reaction). There is evidence that hydroxyl radicals are important in brown-rot, while they can be formed by secondary reactions during lignin breakdown by white-rot fungi. Their involvement in cellulose breakdown creates a range of oxidized sugars. The two reactants of Fenton's reagent can be generated by Fe(II) autoxidation, or by superoxide in reaction with Fe(III). A rapid autoxidation is not possible for complexes with a high Fe(III)/Fe(II) redox potential. Turning to specific pathways for formation of Fenton's reagent, decomposition of Fe(III)-oxalate is probably solely a photochemical process. Lignin peroxidases can act indirectly as a source of superoxide, either by reactions that lead to a peroxyradical, or by 1-electron oxidation of an aliphatic compound creating a strong reductant. Cellobiose dehydrogenase can provide a direct enzymic source for Fenton's reagent (S.M. Kremer and P.M. Wood (1992) Eur. J. Biochem. 208, 807–814). In the experiments as published, hydroxyl radical production was limited by the slow interaction of cellobiose dehydrogenase with O2. This limitation can be removed by the presence of an iron complex with an autoxidizable Fe(lI) state. The successful use of Fenton's reagent by a living organism requires a spatial separation between initiating enzyme(s) and the site of production of hydroxyl radicals. The mobility of the extra electron on Fe(II) by intermolecular transfer may be important for achieving this separation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6976.1994.tb00051.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Continuous monitoring of cellulose oxidation by cellobiose oxidase from Phanerochaete chrysosporium (1992)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 92 (1992), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Cellobiose oxidase activity from Phanerochaete chrysosporium was monitored continuously by two techniques that are independent of the presence of a solid substrate, measuring either ferricyanide by the electrode potential of anaerobic ferricyanide plus ferrocyanide, or O2 with a specific electrode. Both methods demonstrated that microcrystalline cellulose (Avicel) is a substrate for oxidation. All experiments were at pH 4.0 and 30°C. Rates were evaluated for two-electron transfer. For Avicel → ferricyanide, a study of initial rates gave kcat= 0.40 ± 0.05 s−1, much slower than kcat= 3.6 ± 0.3 s−1 with cellobiose as substrate. With Avicel plus 0.2 μM cellobiose oxidase, the rate fell to half its initial value in 3–8 min, indicating a heterogeneity of reducing ends. For Avicel → O2, kcat= 0.057 ± 0.004 s−1. Half maximal rates corresponded to Km(Avicel) = 8 ± 2 gl−1 with ferricyanide, and 3.3 ± 0.5 gl−1 with O2 as acceptor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1992.tb05257.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    USE OF FLUORESCENT GELS IN CHARACTERIZATION OF A MEMBRANE CYTOCHROME c FROM PSEUDOMONAS AERUGINOSA (1980)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 7 (1980), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6941.1980.tb01603.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Two membrane-bound b-type cytochromes in Nitrosomonas europaea (1983)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 20 (1983), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Membranes from Nitrosomonas europaea were found to contain two b-type cytochromes. One had an α-band centred at 562 nm and Em,7=+ 155 mV; the other had an α-band maximum close to 558 nm and Em,7=+ 40 mV. A b-type cytochrome ran at an apparent Mr of 32000 on lithium dodecyl sulphate/polyacrylamide gels at 4°C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1983.tb00140.x
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Continuous monitoring of cellulase action on microcrystalline cellulose (1992)
    Springer
    Applied microbiology and biotechnology 37 (1992), S. 750-755 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Cellobiose oxidase from Phanerochaete chrysosporium was used for continuous monitoring of cellulase action on microcrystalline cellulose (Avicel). Two protocols are described, the parameter monitored being either the decline in electrode potential as ferricyanide is reduced or consumption of dioxygen. Most experiments used a commercial cellulase preparation from Trichoderma reesei and ferricyanide as acceptor. Within 1 min of an addition of cellulase, ferricyanide reduction reached a steady rate. This was converted into a rate of production of substrate for celobiose oxidase, in μmol·min−1. Experiments were conducted either with a constant concentration of cellulase and increasing Avicel, or with constant Avicel and increasing cellulase. Kinetic analysis of the experiments with constant cellulase indicated a K mof 4.8 ± 1.0 (g cellulose)·1−1, which was close to the value predicted from binding studies. The specific activity of the cellulase was measured as 375±25 μmol·(g cellulase)−1·min−1 in experiments with a high cellulose concentration, but was less than half this value when the cellulose was saturated with cellulase. The maximal rate of cellulose degradation was 9.6±1.3 μmol·(g cellulose)−1·min−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00174841
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Ethylene oxidation by Nitrosomonas europaea (1984)
    Springer
    Archives of microbiology 137 (1984), S. 155-158 
    Details
    ISSN: 1432-072X
    Keywords: Ammonia monooxygenase ; Epoxidation ; Ethylene oxidation ; Methylotrophs ; Nitrilying bacterium ; Nitrosomonas europaea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Incubation of whole cells of the nitrifying bacterium Nitrosomonas europaea with ethylene led to the formation of ethylene oxide. Ethylene oxide production was prevented by inhibitors of ammonium ion oxidation, and showed properties implying that ethylene is a substrate for the ammonia oxidising enzyme, ammonia monooxygenase. Endogenous substrates, hydroxylamine, hydrazine and ammonium ions were compared as sources of reducing power in terms of rates and stoichiometries of ethylene oxidation. The highest rates of ethylene oxide formation (15 μmol h-1 mg protein-1) were obtained with hydrazine as donor. The data suggest that at high concentrations of ethylene the rate of oxidation is limited by the rate at which reducing power can be supplied to the monooxygenase, not by an intrinsic V max. Ethylene had an inhibitory effect on the rate of ammonium ion utilisation; an approximate K i of 80 μM was derived, but the results deviated from simple competitive behaviour. Measurement of relative rates of ethylene oxide formation and ammonium ion utilization led to a k cat/K m value for ethylene of 1.1 relative to NH 4 + , or 0.04 relative to the true natural substrate, NH3. The effects of higher concentrations of ethylene oxide on oxygen uptake rates were also investigated. The results imply that ethylene oxide is also a substrate for the monooxygenase, but with a much lower affinity than ethylene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00414458
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    A kinetic study of benzene oxidation to phenol by whole cells of Nitrosomonas europaea and evidence for the further oxidation of phenol to hydroquinone (1985)
    Springer
    Archives of microbiology 143 (1985), S. 302-306 
    Details
    ISSN: 1432-072X
    Keywords: Ammonia monooxygenase ; Benzene oxidation ; Methanotrophs ; Nitrifying bacteria ; Nitrosomonas europaea ; Phenol oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The oxidation of benzene to phenol by whole cells of Nitrosomonas europaea is catalysed by ammonia monooxygenase, and therefore requires a source of reducing power. Endogenous substrates, hydrazine, hydroxylamine and ammonium ions were compared as reductants. The highest rates of benzene oxidation were obtained with 4 mM benzene and hydrazine as reductant, and equalled 6 μmol· h-1·mg protein-1. The specificity of ammonia monooxygenase for benzene as a substrate was determined by measuring k cat/K m for benzene relative to k cat/K m for uncharged ammonia, a value of 0.4 being obtained. Phenol was found to be further hydroxylated to yield hydroquinone. This reaction, like benzene oxidation, was sensitive to the ammonia monooxygenase inhibitor allylthiourea. Catechol and resorcinol were not detected as products of phenol oxidation, implying that at least 88% of the hydroxylation is para-directed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00411254
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Light-driven reduction of oxygen as a method for studying electron transport in the green photosynthetic bacterium Chlorobium limicola (1985)
    Springer
    Archives of microbiology 143 (1985), S. 82-87 
    Details
    ISSN: 1432-072X
    Keywords: Bacterial photosynthesis ; Chlorobium limicola ; Mehler reaction ; Methyl viologen ; Oxygen electrode ; Sulphide oxidation ; Superoxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The use of O2 uptake as a valid assay for non-cyclic photosynthetic electron flow in membranes from Chlorobium limicola is discussed. It is recommended that methyl viologen, catalase and superoxide dismutase should be added to the experimental medium. The addition of methyl viologen more than doubled the rate of O2 uptake observed on illumination with 1 mM sulphide as donor. Superoxide dismutation was shown to be efficient under the experimental conditions by means of standard additions of potassium superoxide dissolved in dimethylsulphoxide. The highest rates of light stimulated O2 uptake were obtained with sulphide as electron donor, and approached 50 μmol O2 · h-1 · mg bacteriochlorophyll c -1 with 0.2 mM sulphide. The presence of 5 mM 2-mercaptoethanol or 3 mM sulphite as electron donor led to lower light stimulated rates of O2 uptake, while 5 mM thiosulphate had little effect. The rates were insensitive to uncoupler. The light stimulated O2 uptake with 0.2 mM sulphide as donor was 20–30% inhibited by 10 μM antimycin A and 50 μM cyanide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00414773
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...