Maize (Zea mays L.) kernel pedicels, including vascular tissues, pedicel parenchyma, placento-chalazal tissue, and the surrounding pericarp, contained two forms of glutamine synthetase (EC 6.3.1.2), separable by anion exchange chromatography under mildly acidic conditions. The earlier-eluting activity (GS(p1)), but not the later-eluting activity (GS(p2)), was chromatographically distinct from t...

The glutaminase activity of glutamine-dependent carbamyl phosphate synthetase (Escherichia coli) and that of the separated light subunit of this enzyme, as well as the glutaminedependent synthetase activity catalyzed by the native enzyme, are inactivated by incubation in air with relatively low concentrations (0.025 to 1 mM) of dithiothreitol; oxidized dithiothreitol does not inhibit. Other mer...

Inhibition of glutamine synthesis reduces astrocyte swelling and associated physiological abnormalities during acute ammonium acetate infusion in anesthetized rats. We tested the hypothesis that inhibition of glutamine accumulation during more prolonged ammonium acetate infusion in unanesthetized rats reduces cortical astrocyte swelling and immunohistochemical changes in astrocytic proteins. Ra...

Catasetum fimbriatum is an epiphytic orchid from South America that has been used for 15 years as a model plant for metabolic and developmental studies in our laboratory. In this work, C. fimbriatum plants were aseptically grown with 6 mol m(-3) of either glutamine or inorganic nitrogen forms (NO(3)(-):NH(4)(+) ratios). The highest biomass accumulation was found in plants supplied with glutamin...

Anthranilate synthetase was purified by ammonium sulfate precipitation and gel filtration from extracts of an episomebearing Escherichia coli mutant grown under conditions of tryptophan pathway derepression. This purification represented an l&fold increase in specific activity over the activity of the derepressedmutant extract. Starch gel electrophoresis and ultracentrifugation revealed only sl...

Most hepatomas contain only traces of glutamine synthetase (GS) although they originate from liver which has high levels of the enzyme (1-3) The H T C cell line which was derived from Morris Hepa toma 7288C retained certain characteristics of liver cells, notably the induction of tyrosine amino transferase (4, 5), while other liver characteristics, among them GS activity, could not be detected ...

The formation of amidase was studied in mutants from Pseudomonas aeruginosa PAO lacking glutamine synthetase activity. It appeared that catabolite repression of amidase synthesis by succinate was partially relieved when cellular growth was limited by glutamine. Under these conditions, a correlation between amidase and urease formation was observed. The results suggest that amidase formation in ...