Ornithine induced more than 36-fold the ornithine decarboxylase activity in confined Ehrlich ascites tumour cells after 3.5 h of continuous perifusion with 0.5 mM ornithine; arginine and glutamine also induced the activity 3- and 4-fold, respectively. The addition of cycloheximide or actinomycin D antibiotics to the perifusion medium confirmed that the regulation of the enzyme synthesis takes p...

Glutamine-dependent carbamyl phosphate synthetase from Escherichia coli can exist in two different conformations which exhibit, respectively, monomer sedimentation coefficients (.&J of 7.3 S and 8.7 S. Both conformations undergo rapid reversible self-association upon addition of potassium ions or ornithine. Formation of the 8.7 S conformation is promoted by the addition of phosphate ions. Low c...

All metazoan cells in culture require either arginine or citrulline for growth (1, 2). The importance of arginine is emphasized by the fact that it is rapidly depleted from the medium in many primary and established cell strains (3). The L-929 fibroblasts maintained in this laboratory and shown to harbor a pleuropneumonia-like infection also demonstrate a.n elevated requirement for this amino a...

The increase in ODC activity during perifusion of Ehrlich carcinoma cells with 0.5 mM ornithine correlates with an increase in 'de novo' synthetized ODC protein. ODC synthesis was followed by immunoprecipitation of equal quantities of 35S-labelled proteins after 10, 20 and 30 min of labelling. In addition, the rate of 'de novo' protein synthesis is very much elevated in cells perifused with sal...

The free amino acid profile of the fruiting bodies of Pleurotus ostreatus was studied in detail. The first evidence for the occurrence of N delta-acetyl-L-ornithine in the mushroom was presented, and 33 ninhydrin-positive compounds were determined, besides N delta-acetyl-L-ornithine. Alanine, glutamic acid, valine, glutamine, glycine and leucine were predominant protein amino acids occurring in...

Carbamoyl phosphate synthetase of pea shoots (Pisum sativum L.) was purified 101-fold. Its stability was greatly increased by the addition of substrates and activators. The enzyme was strongly inhibited by micromolar amounts of UMP (Ki less than 2 mum). UDP, UTP, TMP, and ADP were also inhibitory. AMP caused either slight activation (under certain conditions) or was inhibitory. Uridine nucleoti...

Dundas, Ian E. D. (University of Illinois, Urbana), and H. Orin Halvorson. Arginine metabolism in Halobacterium salinarium, an obligately halophilic bacterium. J. Bacteriol. 91:113-119. 1966.-Arginine was shown to be essential for growth of Halobacterium salinarium strain 1 in a chemically defined medium. Citrulline was the only compound which could substitute for arginine without affecting gro...

UNLABELLED BACKGROUND Residual alcohol effects on physiological and psychological symptoms are commonly experienced the morning after alcohol consumption. The purpose of this study was to assess the effects of L-ornithine on subjective feelings and salivary stress markers the morning after alcohol consumption and to investigate whether L-ornithine acutely accelerates ethanol metabolism. ME...

Previous studies of serine dehydratase (EC 4.2.1.13) and ornithine aminotransferase (EC 2.6.1.13) adaptation in rat liver showed that in rats on a high protein diet, glucocorticoid administration increased serine dehydratase activity while simultaneously reducing the activity of ornithine aminotransferase. The present study examines the role of enzyme synthesis in the expression of these and ot...

Lactic acid bacteria play a pivotal role in many food fermentations and sometimes represent a health threat due to the ability of some strains to produce biogenic amines that accumulate in foods and cause trouble following ingestion. These strains carry specific enzymatic systems catalyzing the uptake of amino acid precursors (e.g., ornithine and lysine), the decarboxylation inside the cell, an...