In-vitro-Versuche über die Methämoglobinbildung durch Chinonderivate

Summary Heubner states that the oxidation of hæmoglobin to methæmoglobin by quinones should be due to a tension between two oxidation-reduction systems, the quinone-hydroquinone system and the hæmoglobin-methæmoglobin system. The authors tried to prove this statement by using various quinones with different oxidation-reduction potentials. An analysis of the results obtained suggests, however, that the oxidation-reduction potential is not the only factor determining the equilibrium. It seems that some other constitutionally conditioned factors also play an important role in this process.Experiments with non-hæmolyzed erythrocytes show that all quinones tested are able to pass through the cellular membrane of the erythrocytes without undergoing any chemical reaction. Thus, the experiments with hæmolyzed solutions and those with intact erythrocytes gave identical results.     

Eine im Alkalischen wirksame Monophosphoesterase aus Hefe

Summary The authors describe a monophosphoesterase isolated from yeast which acts strongly on sodium phenolphthaleinphosphate, phenolphosphate, and-glycerophosphate in an alkaline medium (p _H 8,5–9,1). The enzyme does not need magnesium ions for its activity.     

Die Wirkung von Chinonen auf das Hefewachstum

Summary Certain derivatives ofp-benzoquinone and the naphthoquinones cause a strong inhibition of the growth of yeast. The strongest concentrations of some of these compounds even show a fungicidal potency. The authors discuss the possible mode of action of this inhibition.     

Die Biochemie der Chinone

Ohne Zusammenfassung     

Hemmungswirkung verschiedener Chinone auf die Eiweißspaltung durch Papain

Summary With the intention to clarify the mechanism of action of the antibiotic effect of some quinones the inhibition of the activity of papain by various quinones was measured. The results let it appear improbable that there is any relation between the antibacterial effect of the quinones and their inhibition power on papain. On the other hand a close parallelism was found in the strength of inhibition of the same quinones on papain, urease and catalase. The mechanism of action of the quinone inhibition of these three enzymes must be regarded as a very similar one.

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Ausführliche Veröffentlichung mit weiteren Belegen folgt in den Monatsheften für Chemie (Wien).     

Hemmungswirkungen verschiedener Indophenole auf die Wasserstoff-peroxydzersetzung durch Blutkatalase

Summary Some indophenol derivatives inhibit strongly the activity of blood catalase. These effects were investigated quantitatively and compared with similar effects due to other oxidizing and reducing agents.