glutamine synthetase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: ATP + L-glutamate + NH4+ = ADP + H+ + L-glutamine + phosphate. [RHEA:16169]

Glutamine synthetase (GS) activity refers to the enzymatic process catalyzed by the enzyme glutamine synthetase. This enzyme plays a critical role in nitrogen metabolism by converting glutamate and ammonia into glutamine. This reaction is essential for several key biological functions:

1. **Ammonia detoxification:** Glutamine synthetase removes ammonia from the body, which is a toxic waste product of amino acid metabolism.

2. **Nitrogen assimilation:** Glutamine serves as a nitrogen donor in various metabolic pathways, including the synthesis of amino acids, purines, pyrimidines, and other nitrogen-containing molecules.

3. **Glutamate recycling:** The synthesis of glutamine by GS is linked to glutamate recycling, which is crucial for maintaining glutamate levels for neurotransmission and other essential functions.

4. **Regulation of amino acid metabolism:** Glutamine synthetase activity is tightly regulated to maintain proper levels of glutamine and other amino acids.

The catalytic mechanism of GS involves a two-step reaction:

1. **Activation of glutamate:** Glutamate reacts with ATP to form a γ-glutamyl phosphate intermediate.

2. **Ammonia incorporation:** Ammonia reacts with the γ-glutamyl phosphate intermediate to form glutamine, releasing inorganic phosphate (Pi) as a byproduct.

Glutamine synthetase is a highly regulated enzyme with multiple allosteric sites that control its activity. These regulatory mechanisms ensure that glutamine production is tightly coupled to the cellular demand for nitrogen and other essential metabolites.'
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Proteins (1)

Compounds (1)