scholarly journals Tracer studies on the biosynthesis of amino acids from lactate by Peptostreptococcus elsdenii

1967 ◽  
Vol 105 (1) ◽  
pp. 299-310 ◽  
Author(s):  
H. J. Somerville ◽  
J. L. Peel
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Tricarboxylic Acid Cycle ◽  
Carbon Chain ◽  
Tricarboxylic Acid ◽  
Diaminopimelic Acid ◽  
Reaction Sequence ◽  
Tracer Studies ◽  
Cell Fractions

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.

scholarly journals Utilization in vivo of glucose and volatile fatty acids by sheep brain for the synthesis of acidic amino acids

1966 ◽  
Vol 101 (3) ◽  
pp. 591-597 ◽  
Author(s):  
R M O'Neal ◽  
R E Koeppe ◽  
E I Williams
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
Sheep Brain ◽  
The Brain

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.

METABOLISM OF C14 AMINO ACIDS AND AMIDES IN DETACHED LEAVES

1956 ◽  
Vol 34 (4) ◽  
pp. 423-433 ◽  
Author(s):  
C. D. Nelson ◽  
G. Krotkov
Keyword(s):  
Amino Acids ◽  
Double Bond ◽  
Glutamic Acid ◽  
Broad Bean ◽  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Activity Data ◽  
Acid Cycle ◽  
Bean Leaves

Detached broad bean leaves were placed with their petioles in 0.01 M ammonium nitrate and allowed to carry on photosynthesis in C14O2 for various periods from 12 to 125 min. The radioactivities of the various amino acids formed from C14O2 were determined. In addition, these amino acids were degraded by decarboxylation with ninhydrin. From the specific activity data it was concluded that the amino acid closest to the site of carbon dioxide fixation in photosynthesis was alanine, followed by aspartic and glutamic acids, with the amides farthest removed. From the intramolecular distribution of label it was concluded that asparagine and glutamine were formed from their corresponding amino acids. The labelling in aspartic and glutamic acids was not consistent with the view that these two amino acids are formed from their corresponding α-keto acids produced by operation of the conventional tricarboxylic acid cycle. A C2 plus C2 condensation is postulated for the formation of aspartic acid. A shift in the double bond in the aconitase reaction of the tricarboxylic acid cycle would account for the observed labelling in glutamic acid. When acetate-1-C14 was fed to detached broad bean leaves in the light or dark, the distribution of label in glutamic acid supported the suggestion that there is such a. shift in the double bond in the aconitase reaction. Sodium arsenite, infiltrated into tobacco leaves, inhibited the biosynthesis of asparagine but not that of glutamine.

scholarly journals Metabolic Activity Related to the Potassium Pump in the Midgut of Bombyx Mori Larvae

1985 ◽  
Vol 116 (1) ◽  
pp. 69-78
Author(s):  
P. PARENTI ◽  
B. GIORDANA ◽  
V. F. SACCHI ◽  
G. M. HANOZET ◽  
A. GUERRITORE
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Tricarboxylic Acid Cycle ◽  
Electrical Potential ◽  
Tricarboxylic Acid ◽  
Electrical Potential Difference ◽  
Acid Cycle

The transepithelial electrical potential difference across the isolated midgut of Bombyx mori larvae is dependent on the presence of potassium and is unaffected by the addition of hexoses to perfusion media, whereas it is enhanced by alanine, aspartic acid, glutamic acid and the corresponding 2- oxoacids, glutamine and malate. The midgut enzyme profile indicates that the substrates for the tricarboxylic acid cycle are supplied mainly by amino acid metabolism via transaminases. Accordingly, aminoxyacetate drastically reduces the intestinal transepithelial electrical potential difference stimulated by amino acids. Measurement of the free amino acid concentration in the lumen content, intestinal cells and haemolymph shows that glutamic acid, asparagine and glutamine are accumulated in the cell, whilst the haemolymph is enriched with basic amino acids and with glycine, alanine, serine and tyrosine, the major components of the silk fibroin. Therefore, amino acid metabolism directly related to the tricarboxylic acid cycle seems to be the primary source of energy for the potassium pump activity in B. mori midgut.

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
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Tca Cycle ◽  
Tricarboxylic Acid ◽  
Carbon Skeleton ◽  
The Other ◽  
Rhizobium Japonicum ◽  
Oxalacetic Acid ◽  
The Tca Cycle

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.

scholarly journals The Content of Non-essential Amino Acids in the Grains of Winter and Spring Varieties of Oats (Avena sativa L.) under the Conditions of Central Southern Bulgaria

2013 ◽  
Vol 14 (1) ◽  
pp. 105
Author(s):  
T. Georgieva ◽  
P. Zorovski
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
G Protein ◽  
Aspartic Acid ◽  
Avena Sativa ◽  
Essential Amino Acids

The purpose of this survey is to study the content of non-essential amino acids in four winter (Dunav 1, Ruse 8, Resor 1, Line M-K) and five spring (Obraztsov chiflik 4, Mina, HiFi, Novosadski golozarnest and Prista 2) cultivars of oats grown in Central Southern Bulgaria within the period from 2007 to 2009. The tested cultivars have different contents of non-essential amino acids. Dunav 1 has the highest quantity of glicine (5.12 g/100 g protein) of all the winter cultivars, Ruse 8 has the highest quantity of alanine (5.69 g/100 g protein) and Resor 1 – the highest quantity of arginine (6.14 g/100 g protein). Generally speaking, the spring cultivars have a larger quantity of glutamic acid (from 25.86 to 26.07 g/100 g protein) and proline (from 6.15 to 8.21 g/100 g protein) but a smaller quantity of glycine (from 4.68 to 4.99 g/100 g protein) compared to the winter cultivars. The naked cultivar Mina has the highest quantity of cystine (2.14 g/100 g protein), cultivar Prista 2 has the highest quantity of proline (8.21 g/100 g protein) and glutamic acid (26.07 g/100g protein) and HiFi ranks first in terms of aspartic acid (9.05 g/100 g protein), serine (5.02 g/100 g protein) and tyrosine (2.09 g/100 g protein). In the study we have also established certain relations between non-essential amino acids.

USE OF GLUTAMIC ACID-U-C14 TO DETERMINE NUTRITIONALLY ESSENTIAL AMINO ACIDS FOR LARVAE OF THE BLOW FLY, PHORMIA REGINA

1960 ◽  
Vol 38 (11) ◽  
pp. 1229-1234 ◽  
Author(s):  
R. Kasting ◽  
A. J. McGinnis
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Essential Amino Acids ◽  
Phormia Regina ◽  
Blow Fly ◽  
Isoleucine Leucine ◽  
Low Level ◽  
Third Instar Larvae

The production of C14O2 by third-instar larvae of the blow fly, Phormia regina Meig., after it was injected with glutamic acid-U-C14, indicates that this substrate was metabolized under these conditions. However, the nutritionally essential amino acids lysine, phenylalanine, valine, isoleucine, leucine, and threonine, isolated from the injected larvae, contained little radioactivity. A low level of radioactivity in arginine, histidine, and methionine suggests that they were slowly synthesized. The nutritionally non-essential amino acids alanine, serine, aspartic acid, and proline contained large quantities of radioactivity; tyrosine and glycine were exceptions. These results, in agreement with earlier work that used glucose-U-C14, show that radioactivity data are useful for determining certain of the nutritionally essential amino acids.

The influence of diet on the nitrogenous components passing to the duodenum and through the lower ileum of sheep

1966 ◽  
Vol 166 (1002) ◽  
pp. 63-79 ◽  
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Nitrogen Content ◽  
Aspartic Acid ◽  
Total Nitrogen ◽  
Amino Nitrogen ◽  
Terminal Part ◽  
High Nitrogen ◽  
Low Nitrogen ◽  
Lower Ileum

Analyses of the alimentary contents flowing to the duodenum of sheep during 24 h show that when the sheep are consuming a low-nitrogen diet more total nitrogen and amino nitrogen pass to the duodenum than are eaten daily in the food whereas when the sheep are eating high nitrogen diets, less total nitrogen and less amino nitrogen pass to the duodenum. The disparity between the total nitrogen and amino nitrogen content of the diets largely disappeared by the time the alimentary contents reached the terminal part of the ileum. From 64 to 68% of the nitrogen entering the duodenum and 54 to 64% of the nitrogen in the ileal contents was in the form of amino nitrogen. Proportionately more of the amino nitrogen was in solution in the ileal contents than in the duodenal contents. Losses of amino acids in the stomach when a high-nitrogen diet was consumed were especially large for glutamic acid, aspartic acid, proline, arginine and leucine. They were least for cystine and threonine. Gains of amino acids in the stomach when low nitrogen diets were consumed were all substantial except for proline, where a loss was found when hay and flaked maize were given. When these changes are considered as proportions of the quantities eaten then trends are similar for all acids. Changes in the molar proportions of the amino acids present in hydrolysates of the duodenal and ileal contents are discussed together with the significance of these changes in relation to the nutrition of the sheep.

scholarly journals Neuronal-glial metabolism under depolarizing conditions. A 13C-n.m.r. study

1992 ◽  
Vol 282 (1) ◽  
pp. 225-230 ◽  
Author(s):  
R S Badar-Goffer ◽  
O Ben-Yoseph ◽  
H S Bachelard ◽  
P G Morris
Keyword(s):  
Amino Acids ◽  
Glial Cells ◽  
Tricarboxylic Acid Cycle ◽  
Tricarboxylic Acid ◽  
Acid Cycle ◽  
Maximum Percentage ◽  
Theoretical Maximum ◽  
Metabolic Pool ◽  
Time Courses ◽  
The Individual

Time courses of incorporation of 13C from 13C-labelled glucose and/or acetate into the individual carbon atoms of amino acids, citrate and lactate in depolarized cerebral tissues were monitored by using 13C-n.m.r. spectroscopy. There was no change in the maximum percentage of 13C enrichments of the amino acids on depolarization, but the maxima were reached more rapidly, indicating that rates of metabolism in both glycolysis and the tricarboxylic acid cycle were accelerated. Although labelling of lactate and of citrate approached the theoretical maximum of 50%, labelling of the amino acids was always below 20%, suggesting that there is a metabolic pool or compartment that is inaccessible to exogenous substrates. Under resting conditions labelling of citrate and of glutamine from [1-13C]glucose was not detected, whereas both were labelled from [2-13C]acetate, which is considered to reflect glial metabolism. In contrast, considerable labelling of these two metabolites from [1-13C]glucose was observed in depolarized tissues, suggesting that the increased metabolism may be due to increased consumption of glucose by glial cells. The labelling patterns on depolarization from [1-13C]glucose alone and from both precursors [( 1-13C]glucose plus [2-13C]acetate) were similar, which also indicates that the changes are due to increased consumption of glucose rather than acetate.

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