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  • Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry  (3)
  • Inorganic Chemistry  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Purine, VIII. Über die Umsetzungen heterocyclischer o-Diamino-Verbindungen mit Acetylbrenztraubensäureester (1969)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 4032-4042 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Kondensation von 2.5-Diamino-4-methylamino-6-oxo-1.6-dihydro-pyrimidin (4) mit Acetylbrenztraubensäureester liefert bei pH 1 überraschenderweise 82% 8.9-Dimethylguanin (16) und 15% 6.8-Dimethyl-isoxanthopterin (11), während bei pH 5 erwartungsgemäß 8-Methyl-6-acetonyl-isoxanthopterin (10) resultiert. Nach Isotopenversuchen mit 4-14C-markiertem Acetylbrenztraubensäureester findet sich dieses Atom in der 8-Position des Purin Derivates wieder. Analoge Umsetzungen mit einer Reihe von 4(5)-Amino-5(4)-alkyl(aryl)-amino-pyrimidinen (5-9) bzw. entsprechend substituierten o-Diamino-pyridinen (25,26) und mit N-Methyl-o-phenylendiamin werden beschrieben. pKa-Werte und UV-Spektren der synthetisierten Produkte wurden bestimmt.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19691021210
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  • 2
    Electronic Resource
    Electronic Resource
    Pteridine, LIX. Synthese von 7-Amino-, 7-Hydroxy- und 7-Methoxylumazin-5-oxiden und eine neue Pteridin → Purin-Umwandlung (1973)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 3203-3215 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pteridines, LIX. Synthesis of 7-Amino-, 7-Hydroxy- and 7-Methoxylumazine 5-Oxides and a new Pteridine → Purine Transformation7-Hydroxy- (5,7) and 7-methoxy-6-methyllumazines (6,8) can be converted to the corresponding 5-oxides 12-15 by H2O2 oxidation. Refluxing in acetic anhydride lead to deoxygenation of the 7-methoxylumazine 5-oxides (13,15) whereas the corresponding 7-hydroxy derivatives (12, 14) react under ring contraction to 1,3-disubstituted uric acids (25, 26). A possible reaction mechanism of this pteridine → purine transformation will be discussed on the basis of isotope experiments.
    Notes: 7-Hydroxy- (5, 7) und 7-Methoxy-6-methyllumazine (6, 8) lassen sich durch Oxidation mit H2O2 in die entsprechenden 5-Oxide 12-15 überführen. Beim Kochen mit Acetanhydrid werden die 7-Methoxylumazin-5-oxide (13, 15) zu den Ausgangsverbindungen desoxygeniert, während die entsprechenden 7-Hydroxy-Derivate (12, 14) unter Ringverengung 1,3-disubstituierte Harnsäuren (25,26) liefern. Ein möglicher Reaktionsmechanismus dieser Pteridin → Purin-Umwandlung wird auf der Basis von Isotopenexperimenten diskutiert.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19731061010
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  • 3
    Electronic Resource
    Electronic Resource
    Pteridine, XLVII Struktur von Xanthopterin-peroxid und seine Umwandlung in Melanurensäure (1971)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 104 (1971), S. 3069-3072 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pteridines, XLVII The Structure of Xanthopterin-peroxide and its Transformation into Melanuric AcidThe structure of „xanthopterin-peroxids“ (2) is discussed and a mechanism for its transformation to melanurenic acid (4) by hydrogen peroxide is proposed on the basis of 14C-experiments.
    Notes: Die Struktur des „Xanthopterin-peroxide“ (2) wird diskutiert und für seine Umwandlung in Melanurensäure (4) mittels H2O2 auf der Basis von 14C-Experimenten ein Mechanismus vorgeschlagen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19711041010
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  • 4
    Electronic Resource
    Electronic Resource
    Cell culture techniques for studying insect cuticle (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 6 (1987), S. 217-225 
    Details
    ISSN: 0739-4462
    Keywords: ecdysone ; chitin ; catecholamines ; cockroach ; lepidoptera ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Evidence that biosynthetic pathways critical to the formation of insect cuticle are retained in continuous insect cell lines opens new possibilities for research on the cuticle system. Recent findings indicate that chitin, molting hormone, and catecholamines are all produced by a vesicle cell line derived from embryos of the cockroach Blattella germanica. The chitin that is formed by this cell line is particulate and does not show the characteristic featherlike crystalline structure found in mature cuticle. The molting hormone is produced as ecdysone and is released into the culture medium. The addition of 20-hydroxyecdysone to the cultures increases the production of chitin fourfold. These responses are similar to those found in insect organ cultures.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/arch.940060403
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  • 5
    Electronic Resource
    Electronic Resource
    Metabolism of ecdysteroids by a chitin-synthesizing insect cell line (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 15 (1990), S. 137-148 
    Details
    ISSN: 0739-4462
    Keywords: Blatella germanica ; ecdysone ; cholesterol ; tissue culture ; cell culture ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A chitin-synthesizing cockroach cell line (UMBGE-4) previously shown to secrete ecdysteroids was analyzed for its ability to metabolize potential precursors of ecdysone (e.g., 2-deoxyecdysone, 2,22-dideoxyecdysone, 2,22,25-trideoxyecdysone, and cholesterol). All, except cholesterol, were actively metabolized by UMBGE-4 cells. However, all but 2-deoxyecdysone were converted to polar and hydrolyzable metabolites, and not to ecdysone. Labeling with cholesterol was unsuccessful. Labeling experiments with molting hormones, i.e., ecdysone and 20-hydroxyecdysone, confirmed that this cell line can metabolize ecdysteroids and allowed identification of some of the products. Molting hormones were converted into acetate conjugates and polar conjugates which were often double-conjugates, i.e., polar conjugates of acetate conjugates. Labeling experiments with ecdysone demonstrated that this cell line possesses a low ecdysone 20-hydroxylase activity. The capacity of UMBGE-2 cells, which do not synthesize chitin or ecdysteroids, was also examined. Neither ecdysone nor 20-hydroxyecdysone was significantly metabolized by UMBGE-2 cells. 2-Deoxyecdysone and 2,22-dideoxyecdysone were very slowly metabolized respectively to more polar compounds.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/arch.940150303
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  • 6
    Electronic Resource
    Electronic Resource
    Gut chitin synthase and sterols from larvae of Diaprepes abbreviatus (Coleoptera: Curculionidae) (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 18 (1991), S. 105-117 
    Details
    ISSN: 0739-4462
    Keywords: chitin synthesis inhibitors ; ecdysteroids ; molting hormone ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Gut chitin synthase was characterized and the sterols and ecdysteroids in the sugarcane rootstalk borer weevil, Diaprepes abbreviatus, were identified. An in vitro cell-free chitin synthase assay was developed using larval gut tissues from D. abbreviatus. Subcellular fractionation experiments showed that the majority of chitin synthase activity was located in 10,000g pellets. The gut chitin synthase requires Mg2+ to be fully active: 7-8-fold increases in activity were obtained with 10 mM Mg2+ present in reaction mixture. Calcium also stimulated activity (4-5-fold with 10 mM Ca2+), while Cu+2 completely inhibited at 1 mM. Other monovalent and divalent cations had little or no effect on activity. The pH and temperature optima were 7 and 25°C, respectively. Gut chitin synthesis was activated ca. 50% by trypsin treatments. GlcNAc stimulated chitin synthase activity, but Glc, GlcN and glycerin did not. Polyoxin D, UDP, and ADP inhibited the chitin synthase reaction with I50's of 75 μM, 2.3 mM, and 3.6 mM, respectively. Nikkomycin Z was a potent inhibitor of chitin synthase (91% inhibition at 10 μM). Tunicamycin and diflubenzuron had no effect on the enzyme. The apparent Km and Vmax for the gut chitin synthase were, respectively, 122.5 ± 7.4 μM and 426 ± 19.7 pmol/h/mg protein utilizing UDP-GlcNAc as the substrate. Sterol analyses indicated that cholesterol was the major dietary and larval sterol. HPLC/RIA data indicated that 20-hydroxyecdysone was the major molting hormone.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/arch.940180205
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