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 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 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 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 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.

scholarly journals Continuous C14O2 and CO2 Excretion Studies in Experimental Animals

1956 ◽  
Vol 185 (2) ◽  
pp. 269-274 ◽  
Author(s):  
B. M. Tolbert ◽  
Martha Kirk ◽  
E. M. Baker
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Continuous Measurement ◽  
Specific Activity ◽  
Total Activity ◽  
Large Animal ◽  
Labeled Compounds ◽  
Experimental Animals ◽  
Carbon 14 ◽  
Co2 Excretion

An apparatus has been devised which permits, after administration of labeled compounds to animals, the continuous measurement and recording of CO2 excretion by means of infrared absorption, C14 excretion by ion chambers, and specific activity by a ratio analyzer. Comparative excretion studies have been made using labeled amino acids, fats, fatty acids and sugars. The specific activity and total activity rate curves for breath carbon-14 are markedly different. The generally smooth nature of the specific activity curves gives an excellent indication of the continuous and steady processes by which radioactivity is distributed into the various body pools. Studies have been made with mice, rats, guinea pigs and rabbits. As small an amount as 0.1 µc C14 has been used for an 8-hour study in mice. The instrument can be readily adapted for use in large animal or human studies following administration of small amounts of C14.

BIOSYNTHESIS OF MUSTARD OIL GLUCOSIDES: VI. BIOSYNTHESIS OF GLUCOBARBARIN IN RESEDA LUTEOLA L.

1965 ◽  
Vol 43 (2) ◽  
pp. 189-198 ◽  
Author(s):  
E. W. Underhill
Keyword(s):  
Specific Activity ◽  
Mustard Oil ◽  
Keto Acid ◽  
Carbon 14 ◽  
Acid Analogue ◽  
Phenylbutyric Acid ◽  
Carboxyl Carbon

A number of C14-labelled compounds were fed to Reseda luteola L.; after a 24-hour period of metabolism, the thioglucoside aglycone (5-phenyl-2-oxazolidinethione) was isolated and its specific activity determined. In some instances the aglycone was degraded to determine the distribution of C14.DL-γ-Phenylbutyrine (2-amino-4-phenylbutyric acid) was the most efficient precursor of the aglycone, followed by phenylalanine and acetate; the carboxyl carbon of these compounds was not incorporated into the thioglucoside aglycone. Little or no randomization of C14 in the aglycone resulted from feeding DL-γ-phenylbutyrine-2- and -3-C14, DL-phenylalanine-2- and -3-C14, and acetate-2-C14. The conversion of C14 from 10 additional compounds into the aglycone was less than that from D-glucose-G-C14. Isotope competition experiments suggest that β-benzylmalic acid also may be a precursor. It appears that the C6–C3 aglycone is formed from phenylalanine and acetate via C6–C5 and C6–C4 intermediates (including γ-phenylbutyrine or its keto acid analogue) in a manner analogous to the formation of gluconasturtiin in watercress. The carbon-14 and nitrogen-15 of L-phenylalanine-G-C14-N15 and of DL-γ-phenylbutyrine-2-C14-N15 were not incorporated as a unit into the aglycone of glucobarbarin.

STUDIES ON WHEAT PLANTS USING C14 COMPOUNDS: III. THE UTILIZATION OF ACETATE FOR AMINO ACID BIOSYNTHESIS

1957 ◽  
Vol 35 (1) ◽  
pp. 357-363 ◽  
Author(s):  
E. Bilinski ◽  
W. B. McConnell
Keyword(s):  
Amino Acids ◽  
Specific Activity ◽  
Aromatic Amino Acids ◽  
Carboxyl Group ◽  
Acid Biosynthesis ◽  
Methyl Group ◽  
Medium Activity ◽  
Branched Chain ◽  
Direct Incorporation ◽  
Carboxyl Carbon

Sixteen amino acids were isolated from the gluten of wheat plants, the stems of which had been injected with acetate-1-C14 or -2-C14. With both tracers the C14 labelled amino acids varied markedly from each other in specific activity. Glutamic acid, proline, and arginine were most active, followed by the four-carbon amino acids aspartic acid and threonine, while the short-chain amino acids glycine, alanine, serine, and methionine possessed medium activity. Branched-chain and aromatic amino acids, and the two basic amino acids lysine and histidine were weakly labelled, but showed marked differences from each other not only in specific activity but in the relative amounts of carboxyl and methyl groups of acetate incorporated. Acetate-2-C14 generally gave amino acids of highest activity, but acetate-1-C14 was most effective for labelling glycine, histidine, and serine. Partial degradation by ninhydrin decarboxylation clearly showed that the carboxyl group of acetate tended, in general, to appear to a greater extent in the carboxyl group of amino acids than did the methyl group. Direct incorporation of the carboxyl carbon of acetate in C1 of leucine was observed.

STUDIES ON WHEAT PLANTS USING C14 COMPOUNDS: III. THE UTILIZATION OF ACETATE FOR AMINO ACID BIOSYNTHESIS

1957 ◽  
Vol 35 (6) ◽  
pp. 357-363 ◽  
Author(s):  
E. Bilinski ◽  
W. B. McConnell
Keyword(s):  
Amino Acids ◽  
Specific Activity ◽  
Aromatic Amino Acids ◽  
Carboxyl Group ◽  
Acid Biosynthesis ◽  
Methyl Group ◽  
Medium Activity ◽  
Branched Chain ◽  
Direct Incorporation ◽  
Carboxyl Carbon

Sixteen amino acids were isolated from the gluten of wheat plants, the stems of which had been injected with acetate-1-C14 or -2-C14. With both tracers the C14 labelled amino acids varied markedly from each other in specific activity. Glutamic acid, proline, and arginine were most active, followed by the four-carbon amino acids aspartic acid and threonine, while the short-chain amino acids glycine, alanine, serine, and methionine possessed medium activity. Branched-chain and aromatic amino acids, and the two basic amino acids lysine and histidine were weakly labelled, but showed marked differences from each other not only in specific activity but in the relative amounts of carboxyl and methyl groups of acetate incorporated. Acetate-2-C14 generally gave amino acids of highest activity, but acetate-1-C14 was most effective for labelling glycine, histidine, and serine. Partial degradation by ninhydrin decarboxylation clearly showed that the carboxyl group of acetate tended, in general, to appear to a greater extent in the carboxyl group of amino acids than did the methyl group. Direct incorporation of the carboxyl carbon of acetate in C1 of leucine was observed.

Metabolism of Amino Acids in Plants. I. Changes in the Soluble Amino Acid Fractions of Bushbean Seedlings (Phaseolus vulgaris L.) and the Development of Transaminase Activity

1971 ◽  
Vol 49 (6) ◽  
pp. 709-720 ◽  
Author(s):  
J. C. Forest ◽  
F. Wightman
Keyword(s):  
Amino Acids ◽  
Total Nitrogen ◽  
Total Activity ◽  
Quantitative Composition ◽  
Soluble Nitrogen ◽  
Stages Of Growth ◽  
Etiolated Seedlings ◽  
Protein Amino Acids ◽  
Dark Conditions ◽  
Low Activity

The total nitrogen content of seedlings grown under light or dark conditions remained relatively constant during the first 2 weeks of growth, but there was considerable redistribution of nitrogen from cotyledons to the seedling tissues and appreciable changes occurred in the ratio between insoluble and soluble nitrogen in the different organs. Soluble nitrogen increased in etiolated seedlings to reach 55% of the total nitrogen at 14 days, while in light-grown seedlings the soluble nitrogen reached a peak on the 8th day and thereafter rapidly decreased to 25% of the total nitrogen by the end of 2 weeks. The quantitative composition of the soluble nitrogen fraction, with respect to free protein amino acids, was found to differ considerably, not only between seedlings at different stages of growth, but also between organs taken from seedlings at the same stage of growth under the two light conditions. Asparagine, serine, valine, alanine, and threonine were the amino acids that showed the greatest change in amounts in both types of seedlings. Of the six transaminases investigated, only aspartate, alanine, and asparagine aminotransferase systems showed high total activity. Valine aminotransferase had low activity, and the serine and threonine transaminases were not detected. Development of the different transaminase activities was quite similar in seedlings grown under light or dark conditions. No correlation was observed between the development of transaminase activities and the changes in concentrations of the corresponding free amino acids in these seedlings.

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