The metabolism of L-proline by jack pine seedlings

1971 ◽  
Vol 49 (12) ◽  
pp. 2163-2173 ◽  
Author(s):  
D. J. Durzan ◽  
P. K. Ramaiah
Keyword(s):  
Amino Acids ◽  
Carboxylic Acid ◽  
Glutamic Acid ◽  
Specific Activity ◽  
Jack Pine ◽  
Sharp Drop ◽  
Peroxidase Isoenzyme ◽  
Succinamic Acid ◽  
Pine Seedlings ◽  
Pyrrolidone Carboxylic Acid

The metabolism of L-proline was studied in 6-day-old jack pine seedlings, freshly excised from the nutritive female gametophyte. During the following 24 h, a sharp drop in free amino acids and protein was observed. Although levels of free proline were low, uniformly labeled 14C-L-proline and proline-3, 4-3H served as precursors for the dicarboxylic amino acids and their corresponding amides, glutamine and asparagine, which usually accumulate during germination. The origin of asparagine while unresolved did not involve β-cyanoalanine. Other products of proline metabolism included Δ1-pyrroline-5-carboxylic acid, glutamic acid, and γ-aminobutyric acid. With 14C-proline, radioactivity in alanine and serine resulted presumably from refixation of 14CO2 that was released by the decarboxylation of glutamic acid and other organic acids. The remaining products, e.g. pyrrolidone carboxylic acid, succinamic acid, and succinimide, were more closely related to the fate of glutamine than to proline.Radioactivity in proline and derived amino acids was recovered from soluble proteins separated on polyacrylamide gels. Five fractions revealed a similar diurnal turnover of specific activity. Three of these contained peroxidase isoenzyme activity. The recovery of tritium from peroxidase isoenzymes was related through the metabolism of proline to the intake and metabolism of water as well as to the appearance of enzyme activity in vascular tissues and emerging root and shoot apices.

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.

STUDIES ON WHEAT PLANTS USING CARBON-14 LABELLED COMPOUNDS: X. THE INCORPORATION OF GLUTAMIC ACID-l-C14

1959 ◽  
Vol 37 (1) ◽  
pp. 933-936 ◽  
Author(s):  
W. B. McConnell
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Specific Activity ◽  
Wheat Plant ◽  
Protein Fractions ◽  
Appreciable Amount ◽  
Kernel Development ◽  
Carbon 14

Glutamic acid-1-C14 was injected into the top internode of wheat stems at a stage of growth when kernel development was rapid (71 days after seeding). The plants were harvested 31 days later when they had matured and the incorporation of carbon-14 studied. About one-third of the carbon-14 administered was found in the upper portions of the mature plants, much of the remaining radioactivity having apparently been respired. About 85% of the carbon-14 recovered was found in the kernel. The protein fractions of these were most radioactive, but an appreciable amount of carbon-14 also appeared in the starch. Glutamic acid had the highest specific activity of the amino acids isolated from the gluten, but proline and arginine were also strongly labelled. Since these three amino acids were labelled predominantly in carbon-1 their close metabolic relationship in the wheat plant seems probable.

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.

STUDIES ON WHEAT PLANTS USING C14 COMPOUNDS: VII. UTILIZATION OF PYRUVATE-2-C14

1958 ◽  
Vol 36 (1) ◽  
pp. 381-388 ◽  
Author(s):  
E. Bilinski ◽  
W. B. McConnell
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Active Carbon ◽  
Specific Activity ◽  
Carboxyl Groups ◽  
Gluten Protein ◽  
Carbon 14 ◽  
Soluble Material

Approximately half of the carbon-14 injected into the stems of wheat plants in the form of pyruvate-2-C14 remained in the plant at maturity, 30 days later. Almost 90% of this had accumulated in the kernel. Appreciable activity was found in the major components, protein, starch, ether-soluble material, and a residue termed bran. The amino acids of the gluten protein differed markedly from one another in specific activity. Glutamic acid and the related amino acids, arginine and proline, were most active, their specific activity decreasing in that order. Fifty-two per cent of the carbon-14 in glutamic acid was in carbon-5, while carbon-1 contained 21%. Seventy per cent of the radioactivity of aspartic acid was divided almost equally between the terminal carboxyl groups. The results are similar to those previously observed using acetate-1-C14 as tracer, and it is concluded that administered pyruvate-2-C14 undergoes extensive decarboxylation to form acetate-1-C14. The most active carbon in alanine from the pyruvate-2-C14 was carbon-1. This observation is not in accord with the theory that alanine is formed directly from pyruvate by transamination.

Reduction of nitroblue tetrazolium to formazan by folic acid

2014 ◽  
Vol 68 (5) ◽  
Author(s):  
Cesare Achilli ◽  
Stefania Grandi ◽  
Annarita Ciana ◽  
Cesare Balduini ◽  
Giampaolo Minetti
Keyword(s):  
Amino Acids ◽  
Folic Acid ◽  
Carboxylic Acid ◽  
Glutamic Acid ◽  
Electron Donor ◽  
The Other ◽  
Nitroblue Tetrazolium ◽  
Donor Moiety

AbstractThe reduction of nitroblue tetrazolium (NBT) to formazan by folic acid, N-(4-aminobenzoyl) glutamic acid, and other amino acids was studied in this paper. The reduction involves only one of the two tetrazolium rings of NBT. The reaction is considerably more rapid with folic acid and N-(4-aminobenzoyl) glutamic acid than with the other amino acids under study. The electron donor moiety appears to be the carboxylic acid in the alpha position. N-ethyl-N′(3-dimethylaminopropyl) carbodiimide notably increases the rate of the reaction and promotes the reduction of both tetrazolium rings.

Nitrogen metabolism of Picea glauca. V. Metabolism of uniformly labeled 14C-L-proline and 14C-L-glutamine by dormant buds in late fall

1973 ◽  
Vol 51 (2) ◽  
pp. 359-369 ◽  
Author(s):  
D. J. Durzan
Keyword(s):  
Carboxylic Acid ◽  
Glutamic Acid ◽  
Picea Glauca ◽  
Glutamine Metabolism ◽  
Aminobutyric Acid ◽  
Common Path ◽  
Carbon 14 ◽  
Keto Acids ◽  
Early Fall ◽  
Pyrrolidone Carboxylic Acid

In early fall, the high levels of free arginine nitrogen in spruce buds were eventually replaced by proline nitrogen, and in late spring, glutamine nitrogen accumulated. In late October when levels of free proline nitrogen were high, bud primordia from terminal shoots were excised and exposed to uniformly labeled 14C-L-proline and 14C-L-glutamine. The main early products from 14C-L-proline were Δ1-pyrroline-5-carboxylic acid, glutamic-γ-semialdehyde, and glutamic acid. Later products included glutamine, γ-aminobutyric acid, and to a much lesser extent pyrrolidone carboxylic acid, ornithine, and arginine. In protein, radioactivity was recovered from proline, glutamic acid, and hydroxyproline.Products from 14C-glutamine were mainly glutamic and α-ketoglutaric acid as well as proline, γ-aminobutyric acid, alanine, and pyrrolidone carboxylic acid. In protein, glutamic acid, aspartic acid, and proline contained carbon-14. Results indicated that proline and glutamine were related by their carbon metabolism through a common path involving glutamic acid. However, the main feature of glutamine metabolism was the removal of its α-amino and the amide nitrogen to yield α-keto acids especially α-ketoglutaric acid. The occurrence of α-ketoglutaramic acid could have accounted for succinamic acid and succinimide derived from 14C-L-glutamine.

Effects of tritiated water on the metabolism and germination of jack pine seeds

1971 ◽  
Vol 49 (12) ◽  
pp. 2139-2149 ◽  
Author(s):  
D. J. Durzan ◽  
A. J. Mia ◽  
B. S. P. Wang
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Unit Area ◽  
Tritiated Water ◽  
Jack Pine ◽  
Aminobutyric Acid ◽  
Insoluble Protein ◽  
Amide Content ◽  
Insoluble Protein Fraction ◽  
Inhibited Water

Tritium, imbibed as tritiated water, which evoked the germination of jack pine, was recovered from alcohol-soluble and insoluble components of seeds. At 12 h, tritium labeled nonexchangeably a few but not all free amino acids. By 96 h, all amino acids contained tritium but in seeds killed by heat no radioactive amino acids were detected. Radioactivity in glutamic acid, alanine, proline, and γ-aminobutyric acid implicated key roles for α-ketoacids and semialdehydes during germination. Two neutral fractions accounted for over 80% of the tritium in alcohol-soluble compounds.Levels of tritium above 1.0 mCi/ml water per gram dry seed inhibited water intake after 1 h and inactivated the germination of seeds by 96%. The total soluble N and amide content were also significantly reduced as alanine N increased. Specific activities of glutamine and γ-aminobutyric acid but not of all amino acids were proportional to tritium dose. Radioactivity in glutamine was not associated with the amide N supporting the specific labeling by tritium at the α-carbon of glutamic acid. At high levels of tritium radioactivity was concentrated in the insoluble (protein) fraction and was accompanied by brittleness of tissues and subcellular disruption. Tritium although localized mostly in the cytoplasm was more concentrated per unit area throughout chromatin regions of the nucleus than in the cytoplasm.

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