Glutamine synthetase, synthesis

Feng, J., Atkinson, M.R., McGleary, W, Stock, J.B., Wanner, B.L. and Nrnfa, A.J. (1992). Role of phosphorylated metabolic intermediates in the regulation of glutamine synthetase synthesis in Escherichia coli. J. Bacteriol. 174, 6061-6070. 

Glutamine synthetase, a brain Mn enzyme, is located mainly in astrocytes, and its synthesis may be modulated by nitric oxide (496). Inhibition of this enzyme could be relevant to aging diseases (497). There is evidence that human NT2-N neurons die via ionotropic glutamate receptor-mediated mechanisms when exposed to hypoxia in the presence of glutamate (498). 

L Berlicki, A Obojska, G Forlani, P Kafarski (2005) Design, Synthesis, and Activity of Analogues of Phosphinothricin as Inhibitors of Glutamine Synthetase, J Med Chem 48(20) 6340-6349... 

Nitrogen can also be transported as glutamine. Glutamine synthetase (Section 24.1.2) catalyzes the synthesis of glutamine from glutamate and NH4 + in an ATP-dependent reaction ... 

The activity of glutamine synthetase is also controlled by reversible covalent modification —the attachment of an AMP unit by a phosphodiester bond to the hydroxyl group of a specific tyrosine residue in each subunit (Figure 24.26). This adenylylated enzyme is less active and more susceptible to cumulative feedback inhibition than is the deadenylylated form. The covalently attached AMP unit is removed from the adenylylated enzyme by phosphorolysis. The attachment of an AMP unit is the final step in an enzymatic cascade that is initiated several steps back by reactants and immediate products in glutamine synthesis. 

---