Strukturspezifischer Abbau von Polypeptid-Metall-Komplexen. V. Abbau des Cu2+-Polymyxin-B-Komplexes durch NH2OH

Summary NH₂OH as well as H₂O₂ (previous results^3,4) decompose the Cu₂₊ complex of polymyxin B as can be shown with thin layer chromatography; the spots of the peptide fragments of both reactions were compared.     

Über Struktur und Aktivität der den H2O2-Zerfall katalysierenden Cu2+-Komplexe. — VI. Differenzierung von nativer RNS und nativer DNS bzw. denaturierter DNS auf Grund der katalytischen Eigenschaften

Summary The catalysis of H₂O₂ decomposition by Cu²⁺-complexes of RNA and DNA has been investigated. It is shown that both complexes decompose H₂O₂, but only the Cu²⁺-RNA-system shows peroxidative activity too, e.g. only in this case the nucleotide bases are degraded. Thermal denaturation of DNA also leads to a Cu²⁺-complex with peroxidative activity, the latter being dependent on the degree of denaturation.

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V. Mitteilung:S. Petri, H. Sigel undH. Erlenmeyer, Helv. chim. Acta49, 1778 (1966).

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12. Mitteilung überMetallionen und H ₂ O ₂; 11. Mitteilung:H. Ch. Curtius, P. Anders, R. Zell, H. Sigel undH. Erlenmeyer, Helv. chim. Acta49, 2256 (1966).     

On the stability and the reactions of the H2O+ ion in aqueous solution

Zusammenfassung Theoretische Überlegungen führen zur Annahme, dass das in der Gasphase wohlbekannte Molekülion H₂O⁺ auch in wässeriger Lösung unter geeigneten Bedingungen eine gewisse Stabilität besitzt. Es ist zu erwarten, dass dieses Ion, welches als protoniertes OH-Radikal aufgefasst werden kann, bei Reaktionen in saurer, wässeriger Lösung eine gewisse Rolle spielt.     

Magnetitfördernde Wirkung von Al3+-Ionen bei der Luftoxidation des Fe(OH)2

Summary It has been proved that Fe(OH)₂, precipitated in alkaline solution and oxidated by air-oxygen, transforms to -FeOOH. In presence of A1³⁺, besides -FeOOH magnetite also appears.     

Zur Biochemie autoxydabler,H2O2-bildender Verbindungen

Summary Cytostatic -aminoketones are found to produce H₂O₂ on autoxidation. Possible pathways of radical and peroxidative reactions in cytostatic therapy are discussed.     

Histochemisch differenzierbare Sorten von Muskelfasern im M. latissimus dorsi des Huhnes

Summary The activity of several enzymes in cross sections of the M. latissimus dorsi of the adult chick was examined. In the slow anterior latissimus dorsi muscle — which is thought to be composed of fibres of identical physiological properties — certain topochemical differences of the fibres are described.     

Extracellular Ca2+ and Mg2+ and cellular metabolism of phospholipids.

High extracellular concentration of Ca2+ inhibits the incorporation of 32P into the cellular phospholipids. This effect is more significant in neoplastic than in normal cells, and it is accompanied by an increase of the percentual incorporation into the lecithin fraction.     

Die Abhängigkeit der Ca++-Aufnahme isolierter Mitochondrien des Herzmuskels von der Na+-und K+-Konzentration als mögliche Ursache der inotropen Digitaliswirkung

Summary In isolated mitochondria of heart muscle from rabbits and oxen there is, under suitable conditions, an accumulation of Ca⁺⁺, which is significantly enhanced by elevating the K⁺/Na⁺ quotient of the incubation medium. K-strophanthine (10^–5–10^–7) does not influence the accumulation of Ca⁺⁺ by the mitochondria of heart muscle. Therefore the intracellular increase in exchangeable Ca⁺⁺ observed after digitalis-glycosides could be explained by a decrease of the intracellular K⁺/Na⁺ quotient, which is caused by inhibition of the membrane ATPase and diminishes the capacity for Ca⁺⁺ accumulation in mitochondria.     

L'ozonolyse «anormale» des dérivés allyliques appliquée à la dégradation du manool en oxydes odorants C18H30O2

Summary The semi-industrial production of the odorous oxides IIIab (overall yield 24%) has been achieved by combining the selective epoxidation of manool (I) in a relatively concentrated solution with the ozonolysis of the resulting epoxide (IV).

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Ce travail a fait l'objet d'une communication devant la Société Chimique de Genève, le 8 juin 1962.

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Nous remercions la Direction de la Maison Firmenich & Cie., Genève, ainsi que le Dr.M. Stoll, Directeur scientifique, de l'autorisation de publier ce travail.     

Einbau von H3-thymidin in zellen und gewebe vonHelix pomatia L. (gastropoda,pulmonata)

Summary It has been demonstrated by injections of H³-Thymidine into adult and juvenile snails (Helix pomatia) that the mitotic activity in the central nervous system, the connective tissue and epidermis was generally higher in juvenile animals than in adult ones. Data are given for the amount of triated thymidine labelled nuclei in the tissues, which are investigated.     

Mn2+ electron spin resonance studies on ATP phosphoribosyltransferase fromE. coli

Summary ESR binding studies of Mn²⁺ with each of the substrates and products suggests that substrate bridge complexes are formed in the reaction. This prediction is confirmed, comparing Mn²⁺+ADP and Mn²⁺+ADP+enzyme spectra.We thank V. M. Fernández for helpful discussions.     

Ethanol reduces Ca2+ concentrations in arterial and venous smooth muscle.

The present results, using isolated rat aortic strips and portal vein segments, demonstrate that ethanol (170--430 mM) significantly inhibits calcium uptake in these 2 different types of vascular smooth muscle.