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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 92 (1970), S. 671-677 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Biochemistry 10 (1971), S. 186-192 
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Biochemistry 8 (1969), S. 4372-4375 
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Notes: Abstract Ample evidence exists that the phytotoxic action of sulfur dioxide in plants is initiated and propagated by impairment of their thioredoxin systems, which by their redox status control the light-dark regulation and productivity of chloroplast metabolism. We have shown that oxidized thioredoxin reacts readily with sulfite ions under sulfitolysis of its exposed disulfide bond and formation of an inactive S-sulfonyl thioredoxin. Accumulation of such modified proteins is suggested to mark the specific threshold concentration of SO2 toxicity in a plant. The adverse effects are potentiated intracellularly by an induction of excess H2O2 synthesis which will oxidize additional SH groups and make them susceptible to further sulfitolysis and incapacitation.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Naturwissenschaften 69 (1982), S. 75-81 
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Notes: Abstract DNA replication requires monomeric deoxyribonucleotides, which cannot be regarded as primary products of organic syntheses on a primitive earth. However, the present biosynthetic pathway — reductive elimination of the 2′-OH group from ribonucleotides, catalyzed by ribonucleotide reductases and thioredoxins — suggests an early, polyphyletic combination of protein-nucleotide interactions and metal catalysis. That key process had to precede the upcome of RNA-DNA dualism on the way from RNA-protein protocells to true organisms.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 2530-2544 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Properties of 5′-Deoxynucleoside 5′-Carboxylic Acids and DerivativesA preparative route to 5′-deoxynucleosid- 5′-carbonitriles (3), both of the ribose and deoxyribose series, involves crown ether-catalyzed reaction of nucleoside 5′-tosylates with solid potassium cyanide in organic solvents. O2,5′-Cyclo derivatives of pyrimidine nucleosides can also serve as starting materials. The nitriles 3 require acidic conditions for conversion to the esters 6 of 5′-deoxynucleoside 5′-carboxylic acids (7) which are suitable nucleotide models for biochemical studies. In alkaline solutions compounds 3 undergo rapid elimination of the purine or pyrimidine base. Furthermore the adenine derivative 3a, under addition of the unsaturated sugar fragment 10 yields a new nucleoside 12 in which N6 is inserted in a pyrrolidine ring. The circular dichroism spectra of the new compounds reflect strong electronic interaction between polar C-5′-substituents and the chromophores and are in line with those of other C-5′-modified nucleosides.
    Notes: Die Darstellung von bisher nicht allgemein zugänglichen 5′-Desoxynucleosid-5′-carbonitrilen (3) gelingt sowohl in der Ribo- wie 2′-Desoxyribonucleosidreihe, wenn man Nucleosid-5′-tosylate mit festem KCN unter Kronenether-Katalyse in organischen Lösungsmitteln umsetzt. Auch O2, 5′-Cyclopyrimidinnucleoside eignen sich als Ausgangsmaterial. Aus den Nitrilen 3 sind unter vorzugsweise sauren Reaktionsbedingungen die Ester 6 und aus ihnen die 5′-Desoxynucleosid-5′-carbonsäuren (7) erhältlich, die sich als Nucleotid-Modelle in biochemischen Systemen eignen. In alkalischer Lösung erleiden die Nitrile 3 rasche Eliminierung der Purin- oder Pyrimidinbase. Aus dem Adeninnucleosid 3a entsteht dabei ferner unter Addition des ungesättigten Zuckerfragmentes 10 das an N6 zu einem Pyrrolidin modifizierte Nucleosid 12. Wie in anderen C-5′-modifizierten Nucleosiden zeigen die Circulardichroismus-Spektren der neuen Verbindungen eine starke elektronische Wechselwirkung zwischen polaren C-5′-Substituenten und den Chromophoren an.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 86 (1974), S. 624-634 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ribonucleotid-Reduktasen sind Enzyme, die in teilungsfähigen Zellen die für die DNA-Verdoppelung benötigten Desoxyribonucleotide synthetisieren. Sie besitzen damit eine Schlüsselfunktion für das Wachstum von Mikroorganismen sowie aller pflanzlichen und tierischen Gewebe. Die Enzyme reduzieren alle vier Purin- und Pyrimidinribonucleotide (als 5′-Di- oder -Triphosphate) unter direkter Substitution der 2′-Hydroxygruppe durch Wasserstoff. Physiologische Reduktionsmittel sind die Mercaptogruppen der Thioredoxine, einer Gruppe kleiner Proteine, die aus der oxidierten Form durch NADPH-abhängige Thioredoxin-Reduktasen regeneriert werden. Man kennt zwei Typen von Ribonucleotid-Reduktasen (I und II), die die Wasserstoffübertragung mit Hilfe proteingebundener Eisen-Ionen oder des 5′-Desoxyadenosylcobalamins (Coenzym B12) katalysieren; in beiden Fällen sind ferner Radikale nachweisbar. Zur Regulation der Enzyme dienen Effektornucleotide. Möglicherweise liegt ein homöostatischer Mechanismus vor, der die Versorgung der Zelle mit DNA-Vorläufern sicherstellt.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 99 (1966), S. 634-641 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Darstellung und Eigenschaften des Dimethyläther-α.α′-bis-triphenylphosphoniumbromids und dessen Kondensation zu Derivaten des Oxepins und Furans werden beschrieben.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 99 (1966), S. 642-652 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Synthese von β.β′-disubstituierten Divinyläthern und Divinylthioäthern durch Wittig-Reaktion wird beschrieben. Die entstehenden cis.trans-Isomeren werden getrennt und durch ihre IR- und NMR-Spektren charakterisiert. Die arylsubstituierten Divinyläther sind beständige Verbindungen und werden selbst durch Kochen mit starken Säuren nicht oder nur langsam gespalten.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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