The biosynthesis of aspartic acid, glutamic acid, and alanine in Rhizobium japonicum

1971 ◽  
Vol 17 (5) ◽  
pp. 683-688 ◽  
Author(s):  
Thomas T. Lillich ◽  
Gerald H. Elkan

The biosynthesis of aspartic acid and the incorporation of its carbon skeleton into glutamic acid and alanine was investigated in Rhizobium japonicum. It was found that oxalacetic acid (OAA) occupies a key position in the metabolism of this amino acid and the dissemination of its carbon skeleton into other amino acids. Aspartic acid is formed by two pathways involving the amination of OAA. In one pathway, OAA is synthesized by the tricarboxylic acid (TCA) cycle and in the other by the carboxylation of either pyruvate or phosphoenolpyruvate. The carbon skeleton of aspartic acid can be incorporated into alanine either by deamination to OAA followed by decarboxylation to pyruvate and reamination or directly by decarboxylation of the number four carbon. There are at least two pathways by which aspartic acid carbon is incorporated into glutamic acid. One path involves the synthesis of α-ketoglutarate from OAA via the TCA cycle, the other is a condensation yielding either β-methylaspartate or α-ketoglutarate, which is then converted to glutamate.

1958 ◽  
Vol 4 (6) ◽  
pp. 627-632 ◽  
Author(s):  
Donald J. Reed ◽  
Vernon H. Cheldelin ◽  
Chih H. Wang

The pathways of biosynthesis of alanine, serine, glycine, aspartic acid, and glutamic acid in Penicillium digitntum have been studied by means of tracer techniques, using glucose-2-C14 and glucose-6-C11 as carbon sources. Alanine appears to be derived directly from pyruvate formed in the glycolytic degradation of glucose. Serine is synthesized from glycine, which is in turn derived mainly from a C2 fragment that originates in the C2–C3 cleavage of pentose, a product of phosphogluconate decarboxylation. The biosynthesis of aspartic acid in this organism may involve several pathways. Glutamic acid appears to be synthesized from glucose intermediates via the conventional reactions of the TCA cycle.


1967 ◽  
Vol 105 (1) ◽  
pp. 299-310 ◽  
Author(s):  
H. J. Somerville ◽  
J. L. Peel

Peptostreptococcus elsdenii, a strict anaerobe from the rumen, was grown on a medium containing yeast extract and [1−14C]- or [2−14C]-lactate. Radioisotope from lactate was found in all cell fractions, but mainly in the protein. The label in the protein fraction was largely confined to a few amino acids: alanine, serine, aspartic acid, glutamic acid and diaminopimelic acid. The alanine, serine, aspartic acid and glutamic acid were separated, purified and degraded to establish the distribution of 14C from lactate within the amino acid molecules. The labelling patterns in alanine and serine suggested their formation from lactate without cleavage of the carbon chain. The pattern in aspartic acid suggested formation by condensation of a C3 unit derived directly from lactate with a C1 unit, probably carbon dioxide. The distribution in glutamic acid was consistent with two possible pathways of formation: (a) by the reactions of the tricarboxylic acid cycle leading from oxaloacetate to 2-oxoglutarate, followed by transamination; (b) by a pathway involving the reaction sequence 2 acetyl-CoA→crotonyl-CoA→glutaconate→glutamate.


1957 ◽  
Vol 35 (6) ◽  
pp. 365-371 ◽  
Author(s):  
E. Bilinski ◽  
W. B. McConnell

Glutamic acid, aspartic acid, and threonine isolated from the gluten of wheat plants to which acetate-1-C14 or -2-C14 was administered during growth have been degraded to determine the complete intramolecular distribution of C14. Sixty-three per cent of the activity in glutamic acid arising from acetate-1-C14 was in carbon-5 and 20% in carbon-1; glutamic acid from acetate-2-C14 contained 43% of the activity in carbon-4 and about 18% in each of carbons 2 and 3. Acetate-1-C14 resulted in labelling largely in the terminal carbons of aspartic acid, and acetate-2-C14 preferentially labelled the internal carbons. The results show that the Krebs' citric acid cycle provides a major pathway for the biosynthesis of the dicarboxylic amino acids of wheat gluten.Striking parallelism in the intramolecular distribution of carbon-14 in aspartic acid and threonine demonstrates that these amino acids are closely linked biosynthetically and is in accord with the idea that aspartic acid provides the carbon skeleton for threonine.


1972 ◽  
Vol 18 (6) ◽  
pp. 875-880 ◽  
Author(s):  
W. M. Johnson ◽  
D. W. S. Westlake

The pathway from glutamic acid to α-hydroxyglutaric acid in Peptococcus aerogenes proceeds via α-ketoglutaric acid and is mediated by two NAD-dependent enzymes. One enzyme, an NAD-dependent glutamic acid dehydrogenase, oxidatively deaminates glutamic acid to α-ketoglutaric acid. The other enzyme, α-ketoglutaric acid reductase, reduces α-ketoglutaric acid to α-hydroxyglutaric acid in the presence of NADH. The demonstration of a very low level of α-ketoglutaric acid dehydrogenase activity in crude cell-free extracts indicates that the primary metabolic pathway for glutamic acid carbons proceeds via α-hydroxyglutaric acid and not via the TCA cycle. Potential energy-yielding mechanisms are discussed relative to the known specific distribution of glutamic acid carbon atoms in fermentation products.


1956 ◽  
Vol 34 (12) ◽  
pp. 1704-1708 ◽  
Author(s):  
Arthur Morgan ◽  
Léo Marion

Earlier attempts to feed ornithine-2-C14 to Medicago sativa L. Grimm had failed to produce any labelled stachydrine. Repetition of the work has confirmed this result, and a study of the amino acids present in the plant has shown that the proline also was inactive. Feeding pyridoxine with ornithine-2-C14 to the plant did not produce active stachydrine, but gave rise to radioactive proline. Of the other amino acids present, glycine, aspartic acid, and glutamic acid were also active. A similar feeding experiment with radioactive ornithine and pyridoxine, using older plants, also failed to produce active stachydrine although, as before, the proline was active and so was the keto acids fraction.The results seem to indicate that ornithine may be the precursor of stachydrine, but that the transformation to proline and the methylation to the alkaloid occur at a later stage of growth, possibly at seed formation.


2021 ◽  
pp. 24-32
Author(s):  
Juliet Oluwatominiyi On ◽  
Glory Akpan Bassey ◽  
Mary-Ibenreh Ogaboh Agba ◽  
Aniedi-Abasi Akpan Markson

Aims: To document the amino acid content of six wild edible mushrooms - Lentinus squarrosulus Mont., Auricularia auricular-judae (Bull.) Wettst., Mycetinis copelandii (Desjardin) A.W. Wilson & Desjardin, Baeospora myosura (Fr.) Singer, Pleurotus ostreatus (Jacq. ex. fr) Kummer and Volvariella volvacea (Bull. ex. Fr.) Singer - found in southern Cross River State, Nigeria. Place and duration of study: Department of Plant and Ecological Studies, University of Calabar, Cross River State, Nigeria, between May 2018 and August 2018. Methodology: The amino acids content of these mushrooms were quantitatively estimated. The samples were obtained and analyzed for amino acids on dry weight basis using standard methods. Results: The amino acid analysis quantitatively estimated the alanine, arginine, aspartic acid, cystine, glutamic acid, glycine, histidine, Isoleucine, leucine, lysine, methionine, norleucine, phenylalanine, proline, serine; threonine; tryptophan; tyrosine and valine component of the mushroom samples. All the mushrooms studied contained nine essential, five conditionally essential and four non-essential amino acids with glutamic acid as the most predominant (values ranging from 6.66 to 17.26g/100g protein). Cysteine (0.30-0.48g/100g protein) and methionine (0.64-1-1.7g/100g protein) were the lowest in concentration. The concentrations of five of these essential amino acids phenylalanine (3.55 mg/100g protein), valine (3.62 mg/100g protein), threonine (3.39 mg/100g protein), tryptophan (1.58 mg/100g protein), and lysine (3.23 mg/100g protein) in P. ostreatus were significantly (P≤0.05) higher than found in the other mushrooms. For the nonessential and conditionally essential amino acids, the concentrations of arginine (6.02 mg/100g protein), aspartic acid (6.88 mg/100g protein), cysteine (0.48 mg/100g protein), glutamine (17.26 mg/100g protein) and glycine (2.61 mg/100g protein) in P. ostreatus were significantly higher (P≤0.05) than found in the other mushrooms. Conclusion: This information reveals that mushrooms are potential sources of quality protein with substantial proportion of essential amino acids indicating they can play a significant role in the fight against malnutrition.


1957 ◽  
Vol 35 (1) ◽  
pp. 365-371 ◽  
Author(s):  
E. Bilinski ◽  
W. B. McConnell

Glutamic acid, aspartic acid, and threonine isolated from the gluten of wheat plants to which acetate-1-C14 or -2-C14 was administered during growth have been degraded to determine the complete intramolecular distribution of C14. Sixty-three per cent of the activity in glutamic acid arising from acetate-1-C14 was in carbon-5 and 20% in carbon-1; glutamic acid from acetate-2-C14 contained 43% of the activity in carbon-4 and about 18% in each of carbons 2 and 3. Acetate-1-C14 resulted in labelling largely in the terminal carbons of aspartic acid, and acetate-2-C14 preferentially labelled the internal carbons. The results show that the Krebs' citric acid cycle provides a major pathway for the biosynthesis of the dicarboxylic amino acids of wheat gluten.Striking parallelism in the intramolecular distribution of carbon-14 in aspartic acid and threonine demonstrates that these amino acids are closely linked biosynthetically and is in accord with the idea that aspartic acid provides the carbon skeleton for threonine.


1959 ◽  
Vol 37 (3) ◽  
pp. 439-447 ◽  
Author(s):  
C. D. Nelson ◽  
Paul R. Gorham

Each of 10 C14-labelled amino acids or amides was introduced into young soybean plants through the cut petiole of one primary leaf. The compounds used were asparagine, glutamine, urea, aspartic acid, glutamic acid, glycine, serine, alanine, norleucine, and arginine. The rates of uptake of all the solutions except arginine were in the range 1.0 to 1.5 μl per minute. After 1 to 5 minutes, the distribution of C14 throughout the plants was determined. Each amino acid was translocated as such without conversion to other compounds. From the point of introduction, translocation of each amino acid or amide was mainly downward toward the root; very little was translocated upward. The amount of asparagine or glutamine that was translocated into the primary leaf opposite the cut petiole increased as the leaf aged, while the amount of the other eight compounds decreased as the leaf aged. When asparagine and serine were administered together, serine moved into the young primary leaf while asparagine was excluded. Both excision of the roots and chilling the roots decreased the velocity of downward translocation of aspartic acid indicating that the roots exert a strong "demand" which favors translocation in a downward direction more than an upward direction in the stem.


Metabolites ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 66 ◽  
Author(s):  
Manu Shree ◽  
Shyam K. Masakapalli

The goal of this study is to map the metabolic pathways of poorly understood bacterial phytopathogen, Xanthomonas oryzae (Xoo) BXO43 fed with plant mimicking media XOM2 containing glutamate, methionine and either 40% [13C5] xylose or 40% [13C6] glucose. The metabolic networks mapped using the KEGG mapper and the mass isotopomer fragments of proteinogenic amino acids derived from GC-MS provided insights into the activities of Xoo central metabolic pathways. The average 13C in histidine, aspartate and other amino acids confirmed the activities of PPP, the TCA cycle and amino acid biosynthetic routes, respectively. The similar labelling patterns of amino acids (His, Ala, Ser, Val and Gly) from glucose and xylose feeding experiments suggests that PPP would be the main metabolic route in Xoo. Owing to the lack of annotated gene phosphoglucoisomerase in BXO43, the 13C incorporation in alanine could not be attributed to the competing pathways and hence warrants additional positional labelling experiments. The negligible presence of 13C incorporation in methionine brings into question its potential role in metabolism and pathogenicity. The extent of the average 13C labelling in several amino acids highlighted the contribution of pre-existing pools that need to be accounted for in 13C-flux analysis studies. This study provided the first qualitative insights into central carbon metabolic pathway activities in Xoo.


1966 ◽  
Vol 101 (3) ◽  
pp. 591-597 ◽  
Author(s):  
R M O'Neal ◽  
R E Koeppe ◽  
E I Williams

1. Free glutamic acid, aspartic acid, glutamic acid from glutamine and, in some instances, the glutamic acid from glutathione and the aspartic acid from N-acetyl-aspartic acid were isolated from the brains of sheep and assayed for radioactivity after intravenous injection of [2-(14)C]glucose, [1-(14)C]acetate, [1-(14)C]butyrate or [2-(14)C]propionate. These brain components were also isolated and analysed from rats that had been given [2-(14)C]propionate. The results indicate that, as in rat brain, glucose is by far the best precursor of the free amino acids of sheep brain. 2. Degradation of the glutamate of brain yielded labelling patterns consistent with the proposal that the major route of pyruvate metabolism in brain is via acetyl-CoA, and that the short-chain fatty acids enter the brain without prior metabolism by other tissue and are metabolized in brain via the tricarboxylic acid cycle. 3. When labelled glucose was used as a precursor, glutamate always had a higher specific activity than glutamine; when labelled fatty acids were used, the reverse was true. These findings add support and complexity to the concept of the metabolic; compartmentation' of the free amino acids of brain. 4. The results from experiments with labelled propionate strongly suggest that brain metabolizes propionate via succinate and that this metabolic route may be a limited but important source of dicarboxylic acids in the brain.


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