The action of hydrogen peroxide on amino acids in presence of iron salts and its bearing on photolysis of amino acids

Zusammenfassung Es wurde der Abbau von Aminosäuren durch Wasserstoffsuperoxyd in Gegenwart von Eisensalzen untersucht. Papierchromatographische Analyse zeigte, dass dabei aus-Aminobuttersäure-Alanin und Glycin, aus-Alanin und Serin Glycin entsteht. Die Bildung von-Alanin und Asparaginsäure aus-Aminobuttersäure und von Asparaginsäure aus Glutaminsäure konnte ebenfalls festgestellt werden. Diese Resultate werden in Zusammenhang gebracht mit dem Mechanismus der Photolyse von Aminosäuren in Gegenwart von TiO₂.     

Degradation of phenylalanine in the presence of hydrogen peroxide

Summary UV-irradiation of phenylalanine by 253.7 nm light in the presence of hydrogen peroxide formed 5 ninhydrin reactive products and ammonia. Four of them were identified as aspartic acid, serine, alanine and lysine.Acknowledgments. This work was supported by the Council of Scientific and Industrial Research. Thanks are due to the Head of the Department for facilities and to. Mr.Rakesh C. Sharma for help.     

Degradation of phenylalanine in the presence of hydrogen peroxide.

UV-irradiation of phenylalanine by 253.7 nm light in the presence of hydrogen peroxide formed 5 ninhydrin reactive products and ammonia. Four of them were identified as aspartic acid, serine, alanine and lysine.     

The presence of octopamine in the brain ofHelix aspersa and its action on specific snail neurones

Résumé L'octopamine est présente dans le tissue nerveus l'escargot,Helix aspersa. Elle a un effet fortement inhibitoire sur certains neurones. Ces neurones sont aussi sensibles à la dopamine et à la noradrénaline. Le mécanisme possible de l'action de l'octopamine est discuté.     

The effect of hydrogen peroxide on the cyclin D expression in fibroblasts

Activation of mitogen-activated protein (MAP) kinase is essential for cyclin D1 expression and provides a link between mitogenic signalling and cell cycle progression. Hydrogen peroxide (H₂ O₂ ) activates MAP kinase; however, it is not known whether this leads to cyclin D expression. Sustained expression of cyclin D1 and D2 was observed when Her14 fibroblasts were incu-bated with 3 mM or higher H₂ O₂ concentrations. Similar results were obtained when cells were incubated in the presence of serum (FCS). However, the sustained expres-complex sion of cyclin D1 and D2 upon H₂ O₂ treatment was not due to the MAP kinase pathway, because MAP kinase kinase inhibitors did not inhibit cyclin D expression. Furthermore, cyclin D1 and D2 levels remained constant even after addition of a protein synthesis inhibitor, indicating that the effect of H₂ O₂ was not due to induction of protein synthesis. These results indicate that H₂ O₂ reversibly inhibits the ubiquitin-proteasome dependent degra-dation of cyclin D1 and D2, probably by transiently in-hibiting ubiquitination and/or the proteasome. Received 12 March 2001; received after revision 5 April 2001; accepted 9 April 2001     

The oxidation of glutathione with formic acid and hydrogen peroxide

Zusammenfassung Durch Oxydation von Glutathion mit Wasserstoffsuperoxid in Ameisensäure wurde Glutathion-dihydrosulfoxid erhalten. Glutathion-sulfoxid, N-Acetylglutathion und assoziiertes (reversibel polymerisiertes) Glutathion wurden als Vergleichssubstanzen erstmalig hergestellt.

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This work was supported in part by funds of the U.S.P.H.S.     

Functional properties of lyophilized hemoglobin in the presence of amino acids after 13 months of conservation

Summary Four lyophilisates of hemoglobin, each protected by an amino acid salt, were conserved for 13 months. The determinations carried out (oxyhemoglobin, methemoglobin, p50, Hill's number, and visible spectrum) demonstrated that the hemoglobin had retained its functional properties.     

The presence of free D-amino acids in mouse tissues

The presence of free D-amino acids in mouse kidney, liver, brain, heart, lung, thymus and serum has been shown with an enzymic microdetermination method. The D-amino acid levels were higher in the extracts of kidney and liver than in those from other organs.     

The presence of free D-amino acids in mouse tissues

Summary The presence of free D-amino acids in mouse kidney, liver, brain, heart, lung, thymus and serum has been shown with an enzymic microdetermination method. The D-amino acid levels were higher in the extracts of kidney and liver than in those from other organs.     

The asymmetry of the nucleotide bases and amino acids

Summary Due to the electric polarisation induced by the carbon and nitrogen atoms, the molecules of the nucleotide bases present a stereo-asymmetry. The DNA right-handed double helix is determined by the asymmetry of the nucleotide bases and it is concordant with the right-handed -helix of the polypeptide molecules formed by L-amino acids.     

Photodynamic action of porphyrins on amino acids and proteins. III. Further studies on the hematoporphyrin-sensitized photooxidation of lysozyme

Riassunto L'ematoporfirina forma con il lisozima un complesso in rapporto molare 2:1. Uno dei siti di legame è rappresentato dalla regione della molecola proteica contenente la metionina-12. L'irradiamento con luce assorbita solo dall'ematoporfirina complessata consente, quindi, la fotoossidazione selettiva di tale amminoacido.

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This work received financial support by the Consiglio Nazionale delle Ricerche. The skilful technical assistance of Mr.O. Buso is gratefully acknowledged.     

Chronic hydrogen peroxide intake and peroxide metabolizing enzyme activities in some tissues of mice and rats

Summary Chronic daily intake of 0.5% H₂O₂ in drinking water decreased Se-dependent glutathione peroxidase (Se-GSHPx) activity in rat skeletal muscle, kidney and liver. Non-Se GSHPx activity decreased in kidney. Deprivation of drinking water decreased Se-GSHPx activity in kidney and non-Se GSHPx activity in kidney and liver. H₂O₂ intake decreased activity of catalase in rat skeletal muscle. H₂O₂ intake or water deprivation caused no changes in these enzyme activities in mice.     

Chronic hydrogen peroxide intake and peroxide metabolizing enzyme activities in some tissues of mice and rats

Chronic daily intake of 0.5% H2O2 in drinking water decreased Se-dependent glutathione peroxidase (Se-GSHPx) activity in rat skeletal muscle, kidney and liver. Non-Se GSHPx activity decreased in kidney. Deprivation of drinking water decreased Se-GSHPx activity in kidney and non-Se GSHPx activity in kidney and liver. H2O2 intake decreased activity of catalase in rat skeletal muscle. H2O2 intake or water deprivation caused no changes in these enzyme activities in mice.     

The effect of dietary amino acids on the growth of tumors

Summary In C3H mice, a direct dose response relationship between tumor growth and dietary amino acid is seen for fibrosarcoma and mammary carcinoma, extending over a range the lower limit of which is defined by the minimum amino acid requirements, and the upper limit by the amino acid level found in most stock diets.Supported by Medical Research Council of Canada.