Glutamine Synthetase

Glutamine synthetase (GS) (EC 6.3.1.2) is an enzyme that plays an essential role in the metabolism of nitrogen by catalyzing the condensation of glutamate and ammonia to form glutamine:

Glutamate + ATP + NH3 → Glutamine + ADP + phosphate

Glutamine Synthetase uses ammonia produced by nitrate reduction, amino acid degradation, and photorespiration. The amide group of glutamate is a nitrogen source for the synthesis of glutamine pathway metabolites.

Other reactions may take place via GS. Competition between ammonium ion and water, their binding affinities, and the concentration of ammonium ion, influences glutamine synthesis and glutamine hydrolysis. Glutamine is formed if an ammonium ion attacks the acyl-phosphate intermediate, while glutamate is remade if water attacks the intermediate. Ammonium ion binds more strongly than water to GS due to electrostatic forces between a cation and a negatively charged pocket. Another possible reaction is upon NH2OH binding to GS, rather than NH4+, yields γ-glutamylhydroxamate.

Read more about Glutamine SynthetaseStructure, Mechanism, Biological Function, Classes, Regulation & Inhibition

Other articles related to "glutamine synthetase, glutamine, synthetase":

Glutamine Synthetase - Regulation & Inhibition
... Other inhibitors are the result of glutamine metabolism tryptophan, histidine, carbamoyl phosphate, glucosamine-6-phosphate, cytidine triphosphate (CTD), and adenosine monophosphate (AMP) ... Glutamate is another product of glutamine metabolism however, glutamate is a substrate for GS inhibiting it to act as a regulator to GS.2 Each inhibitor can reduce the activity of the enzyme once all final glutamine ... High concentrations of glutamine-dependent metabolites should inhibit GS activity, while low concentrations should activate GS activity ...
(glutamate-ammonia-ligase) Adenylyltransferase
... Other names in common use include glutamine-synthetase adenylyltransferase, ATPglutamine synthetase adenylyltransferase, and adenosine triphosphateglutamine synthetase adenylyltransferase ...