Abstract
C14-labelled substrates were supplied to leaves, and the labelling patterns in derived amino acids were examined. A new technique is described for the ninhydrin decarboxylation of amino acids separated on paper chromatograms, making use of the Dynacon electrometer. Succinate-1,4-C14, succinate-2,3-C14, pyruvate-1-C14, pyruvate-2-C14, pyruvate-3-C14, C14O2, and glutamate-1-C14were supplied to wheat leaves, and the total C14and carboxyl-C14in alanine, aspartate, glutamate, asparagine, and glutamine were determined. The results indicated that the amino acids and amides were formed mainly from the corresponding Krebs cycle intermediates. Carbon entered the Krebs cycle mainly by decarboxylation of pyruvate, but partly by its carboxylation. Extensive cycling did not occur. Various other suggested pathways, including the conversion of succinate to glutamic acid via succinic semialdehyde and γ-aminobutyrate followed by carboxylation, did not occur.When glucose-UL-C14was supplied to pea or bean seedlings, the labelling pattern in alanine and glutamine indicated their derivation from glucose via glycolysis and Krebs cycle pathways. However, the pattern in asparagine indicated that it may have been formed from products of glyoxalate cycle.
Publisher
Canadian Science Publishing
Cited by
21 articles.
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1. Metabolism, enzymology and possible roles of 4-aminobutyrate in higher plants;Phytochemistry;1990-01
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3. Effects of Light on “Dark” Respiration**Abbreviations are as follows: AMP, adenosine monophosphate; ADP, adenosine diphosphate; ATP, adenosine triphosphate; CoA, coenzyme A; DCMU, dichlorophenyl dimethyl urea; DHAP, dihydroxyacetone phosphate; Fructose-1,6-P2, fructose-1,6-bisphosphate; glucose-6-P, glucose-6-phosphate; GOGAT, glutamate synthase, E.C. 1.4.1.13 (l-glutamate: NADP-oxidoreductase (transaminating); OAA, oxaloacetate; OPPP, oxidative pentose phosphate pathway; Pi, inorganic phosphate; PEP, phosphoenolpyruvate; PGA, 3-phosphoglycerate; PYR, pyruvate; RPPP, reductive pentose phosphate pathway (Calvin cycle); RuBP, ribulose bisphosphate; TCA, tricarboxylic acid.;Metabolism and Respiration;1980
4. Carbon monoxide fixation by plants;Canadian Journal of Botany;1974-08-01
5. Protein Turnover in Plants and Possible Means of Its Regulation;Annual Review of Plant Physiology;1974-06