Labeling patterns in glutamic acid in Nicotiana rustica from carbon-14 dioxide

1967 ◽  
Vol 89 (15) ◽  
pp. 3938-3939 ◽  
Author(s):  
Linda C. Burns ◽  
Robert M. O'Neal ◽  
Roger E. Koeppe
1952 ◽  
Vol 74 (9) ◽  
pp. 2444-2444 ◽  
Author(s):  
Robert J. Speer ◽  
Ammarette Roberts ◽  
Margaret Maloney ◽  
Henry R. Mahler
Keyword(s):  

1963 ◽  
Vol 41 (1) ◽  
pp. 1-7 ◽  
Author(s):  
H. Reisener ◽  
A. J. Finlayson ◽  
W. B. McConnell

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.


1959 ◽  
Vol 37 (1) ◽  
pp. 933-936 ◽  
Author(s):  
W. B. McConnell

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.


1963 ◽  
Vol 41 (3) ◽  
pp. 737-743 ◽  
Author(s):  
H. Reisener ◽  
A. J. Finlayson ◽  
W. B. McConnell ◽  
G. A. Ledingham

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.


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.


1964 ◽  
Vol 96 (8) ◽  
pp. 1133-1137 ◽  
Author(s):  
R. Kasting ◽  
A. J. McGinnis

AbstractGlucose-U-C14 was incorporated into immature larvae of the wheat stem sawfly, Cephus cinctus Nort., by vacuum-infiltration. These insects were too small to be conveniently injected and could not be easily fed on artificial diets. About half of them survived the infiltration treatment. C14O2 was produced by the organism showing that the radioactive substrate was metabolized. Of the amino acids isolated from the larvae, proline, alanine, glutamic acid, serine, aspartic acid, and glycine contained relatively large quantities of carbon-14 indicating biosynthesis, and are classed as nutritionally non-essential. In contrast, arginine, isoleucine, leucine, lysine, phenylalanine, threonine, tyrosine, and valine contained little, if any, radioactivity and are classed as nutritionally essential. The concentrations of some of the amino acids in the larval tissues are also presented.


1961 ◽  
Vol 39 (10) ◽  
pp. 1559-1566 ◽  
Author(s):  
H. Reisener ◽  
W. B. McConnell ◽  
G. A. Ledingham

When uredospores of Puccinia graminis var. tritici race 15B were shaken in a medium containing M/30 phosphate buffer, pH 6.2, and valerate-1-C14, 97% of the radioactivity was removed from the solution in a period of 3 hours. Fifty-five per cent of the carbon-14 was released as carbon dioxide, and 42% was incorporated into the spores. Carbon-14 was found in many cellular components but the water-soluble fraction accounted for 48% of the tracer in the spores. About two thirds of the water-soluble carbon-14 was in a fraction containing amino acids, amides, and peptides, with glutamic acid, glutamine, and γ-aminobutyric acid being highly radioactive. Carbon-5 of glutamic acid and carbon-1 of γ-aminobutyric acid were particularly radioactive. In addition carbon-1 of glutamic acid was appreciably radioactive. The results are consistent with the view that γ-aminobutyric acid was formed by decarboxylation of glutamic acid and that glutamic acid became labelled as a result of β-oxidation of the valerate-1-C14 to yield acetate-1-C14 which in turn was metabolized by the tricarboxylic acid cycle.


1967 ◽  
Vol 13 (2) ◽  
pp. 143-146 ◽  
Author(s):  
W. B. McConnell ◽  
D. F. Horler ◽  
D. W. S. Westlake

Peptococcus aerogenes ferments histidine-α-14C to acetic, butyric, and formic acids. The distribution of carbon-14 in acetic and butyric acids was consistent with that expected if the urocanic acid pathway was used for the metabolism of histidine. Radioactive glutaconic acid also was isolated from such reaction mixtures. Glutamic acid accumulated when histidine was fermented under sodium-deficient conditions.


1958 ◽  
Vol 36 (1) ◽  
pp. 381-388 ◽  
Author(s):  
E. Bilinski ◽  
W. B. McConnell

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.


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