The chloroplastic glutamine synthetase of spinach leaves has been purified to homogeneity using affinity chromatography. This involves a tandem ;reactive blue A-agarose' and ;reactive red-A-agarose' as the final step in the procedure. This procedure results in a yield of 18 milligrams of pure glutamine synthetase per kilogram of starting material. The purity of our enzyme has been demonstrated ...

The first step of nitrogen assimilation in higher plants, the energy-driven incorporation of ammonia into glutamate, is catalyzed by glutamine synthetase. This central process yields the readily metabolizable glutamine, which in turn is at the basis of all subsequent biosynthesis of nitrogenous compounds. The essential role performed by glutamine synthetase makes it a prime target for herbicida...

Bacillus subtilis glutamine synthetase readily reacts with iodoacetamide, producing very specific changes in the catalytic parameters characteristic of the native enzyme. The alkylation reaction is influenced both by substrates and feedback inhibitors of the enzyme; whereas ammonia and glutamate are without effect, Mg2+-ATP enhances the alkylation reaction, and Mn2f-ATP effectively prevents the...

Chicken brain glutamine synthetase has been found to be localized in the cytosolic fraction of this tissue in contrast to its mitochondrial location in chicken liver. Despite this difference in subcellular distribution, the enzyme from brain exhibits the same molecular weight during sodium dodecyl sulfate-polyacrylamide gel electrophoresis, has the same isoelectric point, and is immunochemicall...

Chicken brain glutamine synthetase has been found to be localized in the cytosolic fraction of this tissue in contrast to its mitochondrial location in chicken liver. Despite this difference in subcellular distribution, the enzyme from brain exhibits the same molecular weight during sodium dodecyl sulfate-polyacrylamide gel electrophoresis, has the same isoelectric point, and is immunochemicall...

The final products of the catabolism of arginine that can be utilized as nitrogen sources by Neurospora crassa are ammonium, glutamic acid, and glutamine. Of these compounds, only glutamine represses arginase and glutamine synthetase. We report here the isolation and characterization of a mutant of N. crassa whose arginase, glutamine synthetase, and amino acid accumulations are resistant to glu...

The relationships of five feedback inhibitors for the Bacillus licheniformis glutamine synthetase were investigated. The inhibitors were distinguishable by differences in their competitive relationship for the substrates of the enzyme. Mixtures of l-glutamine and adenosine-5'-monophosphate (AMP) or histidine and AMP caused synergistic inhibition of glutamine synthesis. Histidine, alanine, and g...

The enzymes involved in the assimilation of ammonia by free-living cultures of Rhizobium spp. are glutamine synthetase (EC. 6.o.I.2), glutamate synthase (L-glutamine:2-oxoglutarate amino transferase) and glutamate dehydrogenase (ED I.4.I.4). Under conditions of ammonia or nitrate limitation in a chemostat the assimilation of ammonia by cultures of R. leguminosarum, R. trifolii and R. japonicum ...

Glutamine synthetase [L-glutamate:ammonia ligase (ADP-forming); EC 6.3.1.2] specific activity, cellular content, mRNA abundance, and gene transcription rate increase by greater than 100-fold during adipocyte differentiation of 3T3-L1 cells. In 3T3-L1 adipocytes dexamethasone increases, whereas insulin as well as N6,O2'-dibutyryladenosine 3',5'-cyclic monophosphate decrease, glutamine synthetase...

Glutamine synthetase plays a key role in nitrogen metabolism, thus the fine regulation of this enzyme in Prochlorococcus, which is especially important in the oligotrophic oceans where this marine cyanobacterium thrives. In this work, we studied the metal-catalyzed oxidation of glutamine synthetase in cultures of Prochlorococcus marinus strain PCC 9511 subjected to nutrient limitation. Nitrogen...