scholarly journals A Thioredoxin-Mediated Activation of Glutamine Synthetase and Glutamate Synthase in Synchronous Chlorella sorokiniana

1982 ◽  
Vol 70 (1) ◽  
pp. 113-116 ◽  
Author(s):  
Rudolf Tischner ◽  
Ahlert Schmidt
Keyword(s):  
Glutamine Synthetase ◽  
Glutamate Synthase ◽  
Chlorella Sorokiniana

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.

scholarly journals In Vivo Regulation of Glutamine Synthetase Activity in the Marine Chlorophyll b-Containing CyanobacteriumProchlorococcus sp. Strain PCC 9511 (Oxyphotobacteria)

2001 ◽  
Vol 67 (5) ◽  
pp. 2202-2207 ◽  
Author(s):  
Sabah El Alaoui ◽  
Jesús Diez ◽  
Lourdes Humanes ◽  
Fermı́n Toribio ◽  
Frédéric Partensky ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Starvation ◽  
Glutamate Synthase ◽  
Nitrogen Sources ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Protein Determination ◽  
Physiological Regulation ◽  
Gs Protein

ABSTRACT The physiological regulation of glutamine synthetase (GS; EC6.3.1.2 ) in the axenic Prochlorococcus sp. strain PCC 9511 was studied. GS activity and antigen concentration were measured using the transferase and biosynthetic assays and the electroimmunoassay, respectively. GS activity decreased when cells were subjected to nitrogen starvation or cultured with oxidized nitrogen sources, which proved to be nonusable forProchlorococcus growth. The GS activity in cultures subjected to long-term phosphorus starvation was lower than that in equivalent nitrogen-starved cultures. Azaserine, an inhibitor of glutamate synthase, provoked an increase in enzymatic activity, suggesting that glutamine is not involved in GS regulation. Darkness did not affect GS activity significantly, while the addition of diuron provoked GS inactivation. GS protein determination showed that azaserine induces an increase in the concentration of the enzyme. The unusual responses to darkness and nitrogen starvation could reflect adaptation mechanisms of Prochlorococcus for coping with a light- and nutrient-limited environment.

Influence of nitrogen source and growth status on glutamine synthetase and glutamate synthase activity in Mycobacterium avium

1985 ◽  
Vol 31 (3) ◽  
pp. 211-213
Author(s):  
Charlotte M. McCarthy ◽  
Maria E. Alvarez
Keyword(s):  
Glutamine Synthetase ◽  
Ammonium Chloride ◽  
Mycobacterium Avium ◽  
Cultured Cells ◽  
Specific Activity ◽  
Glutamate Synthase ◽  
Ammonia Concentration ◽  
Apparent Difference ◽  
Growth Status ◽  
Chloride Concentrations

An investigation was made of the activity of glutamine synthetase and glutamate synthase from batch-cultured cells of Mycobacterium avium. The bacteria were grown in medium with ammonium chloride concentrations of 0, 0.1, 0.25, 1, 5, or 25 μmol/mL or with glutamine at 0.1 or 1 μmol/mL. The specific activity of the two enzymes was determined at 0, 22, 45, and 70 h of incubation. Regardless of the ammonia concentration in the medium, glutamate synthase specific activity was two to five times higher in extracts from elongating cells, incubated 22 h, than in those from shortened cells, incubated 45 or 70 h. In contrast, there was no apparent difference in glutamine synthetase specific activity with regard to culture age; however, glutamine synthetase specific activity varied inversely with the concentration of ammonium chloride in the medium. Cells grown in glutamine had high activity of glutamine synthetase.

Exogenous proline application enhances the efficiency of nitrogen fixation and assimilation in chickpea plants exposed to cadmium

2016 ◽  
Author(s):  
Mohammed Nasser Alyemeni ◽  
Qaiser Hayat ◽  
Shamsul Hayat ◽  
Mohammad Faizan ◽  
Ahmad Faraz
Keyword(s):  
Nitrogen Fixation ◽  
Adverse Effects ◽  
Nitrate Reductase ◽  
Glutamine Synthetase ◽  
Glutamate Synthase ◽  
Leaf Nitrogen ◽  
Nitrate Content ◽  
Distilled Water ◽  
Activity Of Enzymes ◽  
Exogenous Proline

Seeds of chickpea were sown in the pots supplemented with 0, 25, 50 or 100 mg of cadmium per kg of soil. At the stage of 30 days after sowing (DAS), the raised plants were sprayed with 20 mM proline except for the control plants which received double distilled water (DDW). The increasing degree of damage caused by the increasing concentration of Cd in soil was partially overcome by proline application. The treatment of 25 mg Cd fed plants with 20 mM proline increased significantly the nodulation parameters, leghemoglobin and carbohydrate content, leaf nitrogen and root nitrate content, activity of enzymes nitrogenase (E.C 1.18.6.1), nitrate reductase (E.C. 1.6.6.1), glutamine synthetase (GS) (E.C 6.3.1.2), glutamate synthase (GOGAT) (E.C 1.4.7.1) and glutamate dehydrogenase (GDH) (E.C 1.4.1.3) over that of the control. The value of these parameters was found to be at par with that of the control in the plants exposed to 50 mg Cd per kg of soil and also treated with 20 mM proline. However, the treatment was not found to be effective in alleviating the adverse effects of 100 mg Cd per kg of soil.

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