The metabolism of 14C-urea by white spruce seedlings in light and darkness

1973 ◽  
Vol 51 (6) ◽  
pp. 1197-1211 ◽  
Author(s):  
D. J. Durzan
Keyword(s):  
Carbon Dioxide ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Urease Activity ◽  
De Novo ◽  
White Spruce ◽  
Acid Synthesis ◽  
Transfer Rna ◽  
Ammonium Ions ◽  
Specific Activities

Weak urease activity was detected in 2-week-old white spruce seedlings. The addition of urea to these seedlings increased urease activity in light compared to darkness. Urease was localized in the cytoplasm mainly in the epidermal cells, and to a lesser extent in vascular tissues and at the shoot apex.In light, the early products of 14C-urea indicated the release of 14C-carbon dioxide and ammonium ions. Radioactivity appeared in the anionic and neutral fractions and then in alanine, serine, and glycine, just as in the fixation of 14C-bicarbonate. By 4 h most radioactivity resided in glutamic acid and alanine. This pattern was associated with increased protein synthesis, and with high levels of free glutamine. Serine, glycine, alanine, and carbamyl aspartic acid had high specific activities.In darkness, radioactivity in alanine persisted, but levels in serine, glycine, and protein were low. Most radioactivity eventually resided in asparagine. Radioactive urea and citrulline were kept at higher levels than in light. Glutamic acid, citrulline, and carbamyl aspartic acid had the greatest specific activities. In light and darkness, carbamyl derivatives were formed more readily from 14C-urea than from 14C-bicarbonate.Carbamyl phosphate was implicated as a precursor of citrulline and arginine as well as for carbamyl aspartic acid. In light, radioactivity was recovered from ribosomal (25, 23, 18, 16, and 5 S) and transfer RNA (4 S). This resided mainly in uracil and cytosine. By contrast, in DNA, radioactivity was recovered mainly from thymine, cytosine, and 5-methylcytosine. In rapidly growing seedlings, urea contributed to de novo nucleic acid synthesis mainly through pyrimidine pathways via carbamyl aspartic acid.

Carbon dioxide fixing pathways of glutamic acid synthesis in the rumen

1970 ◽  
Vol 48 (4) ◽  
pp. 463-468 ◽  
Author(s):  
L. P. Milligan
Keyword(s):  
Carbon Dioxide ◽  
Glutamic Acid ◽  
Distribution Pattern ◽  
Acid Synthesis ◽  
Tricarboxylic Acid ◽  
Simultaneous Occurrence ◽  
Rumen Microorganisms ◽  
Glutamate Synthesis ◽  
The Individual

Rumen contents were incubated with NaHCO3-14C and the pattern of incorporation of 14C into glutamic acid was determined. Label was found in C-1, C-2, and C-5 of glutamic acid. This distribution pattern suggested the simultaneous occurrence of the forward tricarboxylic acid (TCA), the atypical forward TCA, and the reverse TCA pathways of glutamate synthesis in the mixed rumen population; these pathways were estimated to account for 63%, 9%, and 28%, respectively, of the glutamate synthesized by pathways entailing CO2 fixation. The contributions of the individual pathways were not influenced by the ration of the host. The significance of these alternate pathways of glutamate synthesis in the metabolism of rumen microorganisms is discussed.

Stoffwechselregulation durch den Zellwandbaustein Kieselsäure: Polgrößenänderungen von a-Ketoglutarsäure, Aminosäuren und Nucleosidphosphaten

1968 ◽  
Vol 23 (2) ◽  
pp. 268-271 ◽  
Author(s):  
D. Werner
Keyword(s):  
Glutamic Acid ◽  
Aspartic Acid ◽  
Rna Synthesis ◽  
Acid Synthesis ◽  
Centric Diatom ◽  
Free Medium ◽  
Acetyl Coa ◽  
E Coli ◽  
Acid Pool ◽  
Acetyl Coa Pathway

When the centric diatom Cyclotella cryptica is grown in a Si (OH) 4-free medium, the glutamic acid pool decreases within 3 hours to a third of the original value, whereas the aspartic acid pool is reduced by only about 20 per cent. The pools of nucleosid-triphosphates and of glycerol-1-phosphate remain unaffected during this time. The nucleosid-diphosphates pool decreases in the same way as that of aspartic acid. The decrease in the glutamic acid pool precedes the inhibition of total protein synthesis in Si (OH) 4-deficient cells, and a significant decrease in the a-ketoglutarate pool precedes the decrease of the glutamic acid content. Already within 60 minutes ofter incubation in a Si (OH) 4-free medium, the content of a-ketoglutarate is decreased to one third of the normal value. On the other hand, the acetyl CoA pathway (enhanced fatty acid synthesis) is not inhibited. The results suggest, that the Si (OH) 4-metabolism interferes with reactions between the condensing enzyme (acetyl-CoA and oxalacetate) and a-ketoglutarate. The delay between inhibition of protein- and RNA-synthesis and the different changes in the pools of amino acids and nucleosid-triphosphates resemble the regulation of the nucleosid-triphosphate pool and RNA-synthesis in amino acid starved strains of E. coli (EDLIN and NEUHARD) 1, though the primary causes are quite different.

scholarly journals Incorporation of dl-[2−14C]ornithine and dl-[5−14C]arginine in milk constituents by the isolated lactating sheep udder

1968 ◽  
Vol 106 (3) ◽  
pp. 719-724 ◽  
Author(s):  
R. Verbeke ◽  
G. Peeters ◽  
Anne Marie Massart-Leën ◽  
G. Cocquyt
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Glutamic Acid ◽  
Mammary Glands ◽  
Total Radioactivity ◽  
Chemical Degradation ◽  
Mammary Tissue ◽  
Specific Activities ◽  
Plasma Arginine

1. Lactating mammary glands of sheep were perfused for several hours in the presence of dl-[2−14C]ornithine or dl-[5−14C]arginine and received adequate quantities of acetate, glucose and amino acids. 2. In the [14C]ornithine experiment 1·4% of the casein and 1% of the expired carbon dioxide came from added ornithine; 96% of the total radioactivity in casein was recovered in proline; 13% of the proline of casein originated from plasma ornithine. 3. In this experiment the results of chemical degradation of proline of casein as well as relative specific activities in the isolated products are consistent with the view that ornithine is metabolized, by way of glutamic γ-semialdehyde, to proline or glutamic acid. 4. In the [14C]arginine experiments 3% of the casein and 1% of the expired carbon dioxide came from arginine; 84% of the arginine and 9% of the proline of casein originated from plasma arginine. 5. In these experiments the relative specific activities of arginine, ornithine and proline in plasma are in agreement with the view that arginine is metabolized by way of ornithine to proline. The conversion of arginine into ornithine is probably catalysed by arginase, so that arginase in mammary tissue may be involved in the process of milk synthesis.

Conversion of phenylalanine to tyrosine by microorganisms

1968 ◽  
Vol 14 (5) ◽  
pp. 573-578 ◽  
Author(s):  
P. Chandra ◽  
L. C. Vining
Keyword(s):  
Glutamic Acid ◽  
Aspartic Acid ◽  
Marine Bacterium ◽  
Specific Activities ◽  
Hydrolysis Of ◽  
Preferential Incorporation

Fourteen microorganisms of different genera were examined for their ability to convert L-phenylalanine directly to tyrosine. Comparison of the specific activities of phenylalanine, tyrosine, aspartic acid, and glutamic acid isolated after hydrolysis of cells grown in the presence of L-phenylalanine-U-14C indicated that p-hydroxylation of phenylalanine had occurred in all seven species of microfungi tested, and in the marine bacterium, Pseudomonas atlantica. In two basidiomycetes, two yeasts, an actinomycete, and a bacillus, there was no preferential incorporation of radioactivity into tyrosine.

scholarly journals Cardiac Amyloidosis Associated With a Novel Transthyretin Aspartic Acid-18 Glutamic Acid De Novo Mutation

2003 ◽  
Vol 67 (11) ◽  
pp. 965-968
Author(s):  
Takuroh Imamura ◽  
Masamitsu Nakazato ◽  
Yukari Date ◽  
Hiroyuki Komatsu ◽  
Shinya Ashizuka ◽  
...  
Keyword(s):  
Glutamic Acid ◽  
Aspartic Acid ◽  
Cardiac Amyloidosis ◽  
De Novo ◽  
De Novo Mutation

Features of amino acid metabolism in Moniliformis moniliformis (Acanthocephala) in vitro

Parasitology ◽  
1987 ◽  
Vol 94 (3) ◽  
pp. 533-541 ◽  
Author(s):  
P. F. V. Ward ◽  
D. W. T. Crompton
Keyword(s):  
Carbon Dioxide ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Metabolic Pathways ◽  
Volatile Compound ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Moniliformis Moniliformis

Experiments to investigate the metabolism of glycine, L-glutamic acid and L-aspartic acid by Moniliformis moniliformis were carried out by incubating adult worms aerobically for 3 h at 37°C in Tyrode's solution containing either [U-14C]glycine, L-[U-14C]glutamic acid, L-[U-14C]aspartic acid or L-[4-14C]aspartic acid. Much of the glycine and glutamic acid was absorbed by the worms, but little of either was metabolized. Aspartic acid was readily taken up and metabolized. After incubating with L[U-14C]aspartic acid, most radioactivity was found in ethanol and a volatile compound, presumed to be carbon dioxide, with smaller amounts in lactate, alanine, acetate, malate, glucose and succinate. After incubating with L-[4-14C]aspartic acid, most radioactivity was found in lactate and the presumed CO2 with small amounts in alanine, malate and succinate. No radioactivity was found associated with ethanol or acetate. Possible metabolic pathways and suggestions for a relationship between the metabolism of aspartate with that of alanine and serine in this parasite are discussed.

STUDIES ON WHEAT PLANTS USING CARBON-14 COMPOUNDS: XXI. THE METABOLISM OF GLYCINE-2-C14

1964 ◽  
Vol 42 (9) ◽  
pp. 1293-1299 ◽  
Author(s):  
W. B. McConnell
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Glutamic Acid ◽  
Specific Activity ◽  
Total Carbon ◽  
Gluten Protein ◽  
Carbon 14 ◽  
Specific Activities

Glycine-2-C14was administered to 83-day-old wheat plants. The plants were allowed to mature fully and the carbon-14 distribution was then examined. About 80% of the radioactivity injected was recovered in the upper portions of the plant, the kernels themselves containing 66%. Proteins had a higher specific activity than other kernel constituents but the starch contained about one-half the total carbon-14 of the kernels. Glycine and serine were by far the most radioactive amino acids of the gluten protein. They had specific activities of 2720 and 2900 μc/mole C respectively while alanine, histidine, methionine, glutamic acid, and proline had specific activities ranging from 150 to 300 μc/mole C. The specific activities of carbons 1 and 2 of glycine recovered from the protein were 550 and 4900 μc/mole respectively while the specific activities of carbons 1, 2, and 3 of serine were 490, 4300, and 3100 μc/mole respectively. The results confirm previous views regarding extensive interconversion of glycine and serine in maturing wheat. Extensive labelling in carbon 3 of serine is interpreted as evidence that glycine is degraded to "active formaldehyde" and carbon dioxide.

scholarly journals Aspartate Biosynthesis Is Essential for the Growth of Streptococcus thermophilus in Milk, and Aspartate Availability Modulates the Level of Urease Activity

2007 ◽  
Vol 73 (18) ◽  
pp. 5789-5796 ◽  
Author(s):  
Stefania Arioli ◽  
Christophe Monnet ◽  
Simone Guglielmetti ◽  
Carlo Parini ◽  
Ivano De Noni ◽  
...  
Keyword(s):  
Aspartic Acid ◽  
Phosphoenolpyruvate Carboxylase ◽  
Parent Strain ◽  
Urease Activity ◽  
Streptococcus Thermophilus ◽  
Defined Medium ◽  
Lactobacillus Delbrueckii ◽  
Chemically Defined Medium ◽  
Ammonium Ions ◽  
Carboxylase Activity

ABSTRACT We investigated the carbon dioxide metabolism of Streptococcus thermophilus, evaluating the phenotype of a phosphoenolpyruvate carboxylase-negative mutant obtained by replacement of a functional ppc gene with a deleted and inactive version, Δppc. The growth of the mutant was compared to that of the parent strain in a chemically defined medium and in milk, supplemented or not with l-aspartic acid, the final product of the metabolic pathway governed by phosphoenolpyruvate carboxylase. It was concluded that aspartate present in milk is not sufficient for the growth of S. thermophilus. As a consequence, phosphoenolpyruvate carboxylase activity was considered fundamental for the biosynthesis of l-aspartic acid in S. thermophilus metabolism. This enzymatic activity is therefore essential for growth of S. thermophilus in milk even if S. thermophilus was cultured in association with proteinase-positive Lactobacillus delbrueckii subsp. bulgaricus. It was furthermore observed that the supplementation of milk with aspartate significantly affected the level of urease activity. Further experiments, carried out with a p ureI -gusA recombinant strain, revealed that expression of the urease operon was sensitive to the aspartate concentration in milk and to the cell availability of glutamate, glutamine, and ammonium ions.

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