scholarly journals Influence of light and mineral nitrogen forms on the activity of some enzymes in Cucumis sativus L. cotyledons

2015 ◽  
Vol 48 (3) ◽  
pp. 443-452 ◽  
Author(s):  
G. Kubik-Dobosz ◽  
K. Soroka
Keyword(s):  
Amino Acids ◽  
Glutamine Synthetase ◽  
Glutamate Dehydrogenase ◽  
Cucumis Sativus ◽  
Aspartate Aminotransferase ◽  
Alanine Aminotransferase ◽  
Glutamate Synthase ◽  
Mineral Nitrogen ◽  
Nitrogen Forms ◽  
Cucumis Sativus L

It was demonstrated that when nitrogen was deficient in the medium, the activity of glutamine synthetase (GS), glutamate dehydrogenase (GDH), alanine aminotransferase (GPT) and aspartate aminotransferase (GOT) in etiolated cucumber cotyledons was higher than in those of seedlings growing under light. When the plants grew on nitrate or ammonium medium, light stimulated GS activity and depressed that of GDH and GOT, without changing the activity of GPT. It was found that the influence of the form of mineral nitrogen on the activity of the studied enzymes was dependent on light. On the basis of the results. obtained, the contribution of the GS glutamate synthase system and GDH to the incorporation of the taken up nitrogen into the amino acids in light and in darkness is discussed.

scholarly journals The effect of ammonium ions on the activity of glutamate dehydrogenase, alanine aminotransferase and aspartate aminotransferase in Cucumis sativus L. seedlings

2014 ◽  
Vol 50 (3) ◽  
pp. 429-436
Author(s):  
Genowefa Kubiak-Dobosz
Keyword(s):  
Glutamate Dehydrogenase ◽  
Cucumis Sativus ◽  
Aspartate Aminotransferase ◽  
Alanine Aminotransferase ◽  
Ammonium Ions ◽  
Cucumis Sativus L ◽  
Factors Affecting ◽  
Cucumber Seedlings ◽  
Young Leaves ◽  
Medium Activity

Changes in the activity of glutamate dehydrogenase (GDH), alanine aminotransferase (GPT) and aspartate aminotransferase (GOT) were studied in various organs of <em>Cucumis sativus</em> L. seedlings in relation to the uptake of mineral nitrogen (in form of N0<sub>3</sub><sup>-</sup> or NH<sub>4</sub><sup>+</sup> ) from the medium. Activity of GDH, GPT, and GOT was higher in young leaves and roots of cucumber seedlings if the plants developed- in an ammonium medium. No similar changes of aminotransferases activity were noted in the cotyledons. Factors affecting varying effect of ammonium ions upon GPT and GOT activity are discussed for particular organs of cucumber seedlings.

Regulation of Glyconeogenesis from Amino Acids by Acetate in Tetrahymena pyriformis

1973 ◽  
Vol 51 (4) ◽  
pp. 323-331 ◽  
Author(s):  
C. Mavrides
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Glutamate Dehydrogenase ◽  
Aspartic Acid ◽  
Growth Medium ◽  
Aspartate Aminotransferase ◽  
Alanine Aminotransferase ◽  
Sodium Acetate ◽  
Tetrahymena Pyriformis

The regulation of glyconeogenesis from amino acids by acetate was studied in Tetrahymena pyriformis. Alanine aminotransferase and glutamate dehydrogenase were repressed by 0.1% sodium acetate in the growth medium. Incorporations into the glycogen of washed cells from the respective isotopically labelled amino acids were similarly suppressed.Incorporations into glycogen from uniformly 14C-labelled L-serine, L-leucine, L-isoleucine, L-tyrosine, and DL-β-14C-tyrosine were also suppressed by prior growth in a medium supplemented with 0.1% or 0.3% acetate. Percentage incorporation into glycogen was highest from tyrosine, followed by leucine, isoleucine, and alanine, and lowest from glutamic acid and serine.Supplementation of the medium with 0.25% glucose resulted in repression of the above two enzymes and suppression of incorporation into glycogen from amino acids.Incorporation of aspartic acid into glycogen was negligible and was variously and minimally affected by growth in glucose- or acetate-supplemented media. Aspartate aminotransferase was affected in a like manner.Glycogen content was not significantly affected by growth in media supplemented with 0.1% or 0.3% acetate. On the whole, the data suggest that acetate spares amino acids for glyconeogenesis by a mechanism which entails repression of amino-acid-catabolizing enzymes.

Ammonia, glutamine, and asparagine: a carbon–nitrogen interface

1988 ◽  
Vol 66 (10) ◽  
pp. 2103-2109 ◽  
Author(s):  
K. W. Joy
Keyword(s):  
Glutamine Synthetase ◽  
Glutamate Dehydrogenase ◽  
Higher Plants ◽  
Amino Nitrogen ◽  
Glutamate Synthase ◽  
Dinitrogen Fixation ◽  
Similar Function ◽  
Metabolic Processes ◽  
Organic Form ◽  
Primary Input

In plants, the primary input of nitrogen (obtained from the soil or from symbiotic dinitrogen fixation) occurs through the assimilation of ammonia into organic form. Synthesis of glutamine (via glutamine synthetase) is the major, and possibly exclusive, route for this process, and there is little evidence for the participation of glutamate dehydrogenase. A variety of reactions distribute glutamine nitrogen to other compounds, including transfer to amino nitrogen through glutamate synthase. In many plants asparagine is a major recipient of glutamine nitrogen and provides a mobile reservoir for transport to sites of growth; ureides perform a similar function in some legumes. Utilisation of transport forms of nitrogen, and a number of other metabolic processes, involves release of ammonia, which must be reassimilated. In illuminated leaves, there is an extensive flux of ammonia released by the photorespiratory cycle, requiring continuous efficient reassimilation. Aspects of ammonia recycling and related amide metabolism in higher plants are reviewed.

Bio-available amino acids and mineral nitrogen forms in soil of moderately mown and abandoned mountain meadows

Amino Acids ◽  
2006 ◽  
Vol 34 (2) ◽  
pp. 301-306 ◽  
Author(s):  
P. Formánek ◽  
K. Rejšek ◽  
V. Vranová ◽  
M. V. Marek
Keyword(s):  
Amino Acids ◽  
Mineral Nitrogen ◽  
Nitrogen Forms ◽  
Mountain Meadows
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