Halobacillus halophilus, a moderately halophilic bacterium isolated from salt marshes, produces various compatible solutes to cope with osmotic stress. Glutamate and glutamine are dominant compatible solutes at mild salinities. Glutamine synthetase activity in cell suspensions of Halobacillus halophilus wild type was shown to be salt dependent and chloride modulated. A possible candidate to cat...

Nitric oxide is postulated to be involved in the pathophysiology of neurological disorders due to hypoxia/ anoxia in brain due to increased release of glutamate and activation of N-methyl-D-aspartate receptors. Reactive oxygen species have been implicated in pathophysiology of many neurological disorders and in brain function. To understand their role in anoxia (hypobaric hypoxia) and reperfusi...

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...

Regulation of glnA expression and glutamine synthetase I activity was analyzed in Corynebacterium glutamicum. Transcription is regulated by the global repressor protein AmtR, essential for derepression of glnA transcription are GlnK and uridylyltransferase, key proteins of the C. glutamicum nitrogen regulatory system. Glutamine synthetase I activity is controlled by adenylylation/deadenylylatio...

Carbamoyl phosphate synthetase from Escherichia coli catalyzes the formation of carbamoyl phosphate from ATP, bicarbonate, and glutamine. The amidotransferase activity of this enzyme is catalyzed by the smaller of the two subunits of the heterodimeric protein. The roles of four conserved histidine residues within this subunit were probed by site-directed mutagenesis to asparagine. The catalytic...

ffects of L-asparagine and L-glutamine on growth, pigments content and metabolism of haseolus vulgaris plants, at two stages of plant growth and development in was investigated in icropropagated tissues (in vitro). In general, all growth parameters increased by 1 & 2 mM sparagine or glutamine treatments while decreased in response to other concentrations (3, 4 & 5 M), Similarly total carbohydra...

Childhood acute lymphoblastic leukaemia is treated by combination chemotherapy with a number of drugs, almost always including the enzyme L-asparaginase (ASNase). Although the initial remission rate is quite high, relapse and associated drug resistance remain a problem. In vitro studies have demonstrated an adaptive increase in asparagine synthetase (AS) expression in ASNase-resistant cells, wh...

Glutamine synthetase and glutaminase activities in human cirrhotic liver tissues and hepatocellular carcinomas were determined for comparison with normal liver tissues. In hepatocellular carcinoma, glutamine synthetase activity was approximately one-third of that in normal liver, whereas no detectable change in the enzyme activity was observed in cirrhotic liver. Phosphate-dependent and phospha...

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...