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.

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

1959 ◽  
Vol 37 (8) ◽  
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.

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.

STUDIES ON WHEAT PLANTS USING CARBON-14 COMPOUNDS: XV. UTILIZATION OF SERINE-1-C14 AND SERINE-3-C14

1961 ◽  
Vol 39 (7) ◽  
pp. 1107-1111 ◽  
Author(s):  
W. B. McConnell ◽  
A. J. Finlayson
Keyword(s):  
Amino Acids ◽  
Specific Activity ◽  
Protein Fractions ◽  
Carbon 14 ◽  
Stages Of Growth ◽  
Protein Amino Acids ◽  
Late Stages ◽  
Carboxyl Carbon ◽  
Soluble Material ◽  
Preferential Incorporation

Thirty-five per cent and 43% of the carbon-14 from DL-serine-1-C14 and L-serine-3-C14, respectively, were found in the mature kernels of wheat plants to which the above tracers were administered by injection into the stem during late stages of growth. Total recoveries of carbon-14 in upper portions of the plant were 40% and 35% respectively. Radioactivity was extensively distributed among major kernel components with protein fractions having a somewhat greater specific activity than starch and ether-soluble material. Carbon-14 from both tracers was incorporated into all of the protein amino acids isolated, notable features being an extensive labelling of carboxyl carbon of glycine when DL-serine-1-C14 was used and preferential incorporation of serine carbon-3 into histidine. The results are in accord with the view that conversion of serine to glycine occurs largely by loss of serine carbon-3 and that little or no glycine is formed from serine via decarboxylation.

STUDIES ON WHEAT PLANTS USING CARBON-14 COMPOUNDS: XII. UTILIZATION OF SERINE-C14 WITH SPECIAL REFERENCE TO GLYCINE LABELLING

1960 ◽  
Vol 38 (6) ◽  
pp. 533-538 ◽  
Author(s):  
R. Nath ◽  
W. B. McConnell
Keyword(s):  
Amino Acids ◽  
Special Reference ◽  
Specific Activity ◽  
High Specific Activity ◽  
Wheat Plant ◽  
Total Carbon ◽  
Plant Parts ◽  
Carbon 14 ◽  
Direct Incorporation

Serine-C14 (uniformly labelled) was injected into the top internode of wheat plant stems and the distribution of carbon-14 in the mature plants (harvested 24 days after injection) was studied. Fifty-six per cent of the carbon-14 injected was found in upper plant parts but only trace amounts occurred below the top internode. The kernels contained 48% of the tracer injected while only 4% remained in the stem. Gluten had the highest specific activity of any major kernel component, serine and glycine accounting for one third of the total carbon-14 of the protein. The high specific activity of serine in gluten indicates its direct incorporation into kernel proteins. The specific activity of the glycine was almost equal to that of serine. Since similar experiments with glycine-1-C14 have yielded gluten with highly radioactive serine-1-C14, the ready interconvertibility of these two amino acids is demonstrated. The results indicate that interconversion takes place, at least in part, by the reversible condensation of "active" formate with carbon-2 of the glycine but that alternate pathways may also operate.

STUDIES ON WHEAT PLANTS USING CARBON-14 COMPOUNDS: XII. UTILIZATION OF SERINE-C14 WITH SPECIAL REFERENCE TO GLYCINE LABELLING

1960 ◽  
Vol 38 (1) ◽  
pp. 533-538 ◽  
Author(s):  
R. Nath ◽  
W. B. McConnell
Keyword(s):  
Amino Acids ◽  
Special Reference ◽  
Specific Activity ◽  
High Specific Activity ◽  
Wheat Plant ◽  
Total Carbon ◽  
Plant Parts ◽  
Carbon 14 ◽  
Direct Incorporation

Serine-C14 (uniformly labelled) was injected into the top internode of wheat plant stems and the distribution of carbon-14 in the mature plants (harvested 24 days after injection) was studied. Fifty-six per cent of the carbon-14 injected was found in upper plant parts but only trace amounts occurred below the top internode. The kernels contained 48% of the tracer injected while only 4% remained in the stem. Gluten had the highest specific activity of any major kernel component, serine and glycine accounting for one third of the total carbon-14 of the protein. The high specific activity of serine in gluten indicates its direct incorporation into kernel proteins. The specific activity of the glycine was almost equal to that of serine. Since similar experiments with glycine-1-C14 have yielded gluten with highly radioactive serine-1-C14, the ready interconvertibility of these two amino acids is demonstrated. The results indicate that interconversion takes place, at least in part, by the reversible condensation of "active" formate with carbon-2 of the glycine but that alternate pathways may also operate.

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

1958 ◽  
Vol 36 (4) ◽  
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.

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 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.

THE METABOLISM OF VALERATE-2-C14 BY UREDOSPORES OF WHEAT STEM RUST

1963 ◽  
Vol 41 (1) ◽  
pp. 1-7 ◽  
Author(s):  
H. Reisener ◽  
A. J. Finlayson ◽  
W. B. McConnell
Keyword(s):  
Carbon Dioxide ◽  
Glutamic Acid ◽  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
High Specific Activity ◽  
Water Soluble ◽  
Buffer Solution ◽  
Wheat Stem Rust ◽  
Carbon 14 ◽  
Water Soluble Extract

When uredospores of Puccinia graminis var. tritici race 15B were shaken in a medium containing M/30 phosphate buffer, pH 6.2, and valerate-2-C14, about 88% of the radioactivity was removed from the buffer solution in a period of 3 hours. About 40% of the carbon-14 taken from the buffer was found in a water-soluble extract of the spores and about 15% was respired as carbon dioxide. The result is compared with an earlier report that carbon 1 of valerate is more extensively released as carbon dioxide and less extensively incorporated into spore components. Glutamic acid, glutamine, γ-aminobutyric acid, and alanine of high specific activity were isolated. It was estimated from partial degradation that more than one-half of the carbon-14 of glutamic acid occurred in position 4 and that carbon 5 was very weakly labelled. Citric acid was also of high specific activity and was labelled predominantly in the internal carbons.It is concluded that respiring rust spores utilize externally supplied valerate by β-oxidation, which releases carbons 1 and 2 in a form which is metabolized as acetate by the tricarboxylic acid cycle.

THE METABOLISM OF PROPIONATE BY WHEAT STEM RUST UREDOSPORES

1963 ◽  
Vol 41 (3) ◽  
pp. 737-743 ◽  
Author(s):  
H. Reisener ◽  
A. J. Finlayson ◽  
W. B. McConnell ◽  
G. A. Ledingham
Keyword(s):  
Carbon Dioxide ◽  
Amino Acids ◽  
Glutamic Acid ◽  
Stem Rust ◽  
Water Extract ◽  
Hot Water ◽  
Insoluble Residue ◽  
Soluble Carbohydrates ◽  
Wheat Stem Rust ◽  
Carbon 14

When uredospores of wheat stem rust were shaken for 3 hours with phosphate buffer (pH 6.2) containing propionate-1-C14, -2-C14, or -3-C14, about 55% of the carbon-14 was removed from the solution. With propionate-1-C14, most of the carbon-14 taken up was released as carbon dioxide-C14, whereas about 20% and 31% of propionate carbon 2 and carbon 3, respectively, was incorporated into the spores. The specific activity of a fraction consisting of the free amino acids of a hot-alcohol and hot-water extract of the spores increased markedly with increase in the position number of propionate in which the carbon-14 was located. A similar relation was observed for other fractions such as soluble carbohydrates, ether-soluble material, organic acids, and insoluble residue from spores. The most active amino acids isolated were glutamic acid, γ-aminobutyric acid, and alanine. Partial degradations showed that with propionate-2-C14 the carboxyl groups of glutamic acid were especially radioactive, whereas with propionate-3-C14 the internal carbons were most radioactive.It is concluded that propionate metabolism in the rust spores involved conversion of carbon 1 to carbon dioxide, and utilization of carbons 2 and 3 as acetate with carbon 2 behaving as the carboxyl carbon.

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