glutamine synthetase

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Related to glutamine synthetase: glutaminase, glutamate synthase

glu·ta·mine syn·the·tase

an enzyme that catalyzes the reaction of l-glutamate, ammonia, and ATP to glutamine, ADP, and orthophosphate; one of the few known mammalian enzymes that uses ammonium ion as a substrate under physiologic conditions.


An intronless gene on chromosome 1q31 that encodes a glutamine synthetase, which catalyses the synthesis of glutamine from glutamate and ammonia. Glutamine is a key source of energy and is involved in cell proliferation, inhibition of apoptosis, and cell signalling. GLUL is expressed during early foetal stages, and plays an important role in controlling pH by removing ammonia from circulation.

Molecular pathology
GLUL mutations are associated with congenital glutamine deficiency.
References in periodicals archive ?
Diagnostic value of HSP70, glypican 3, and glutamine synthetase in hepatocellular nodules in cirrhosis.
Ma, "The role of glutamine synthetase isozymes in enhancing nitrogen use efficiency of N-efficient winter wheat," Scientific Reports, vol.
In peripheral tissues once ammonia and glutamate combine to form glutamine through the action of the glutamine synthetase enzyme, the glutamine is exported from the tissue and transported through the blood to the liver where the free ammonia is released through the action of the glutaminase enzyme.
The results of our research showed that the increase of nitrogen fertilizers dose did not lead to the increase of activity of glutamine synthetase. Thus, the introduction of 2/3 of the calculated nitrogen norm in the tillering period suppressed enzyme's activity a little--0.5 unit/mg of protein, whereas 1/3 of nitrogen increased the activity of glutamine synthetase up to 0.8 unit/mg of protein.
Inhibition of nitrogen-fixing activity of cianobiont affects the localization of glutamine synthetase in hair cells of Azolla.
Its assimilation is then enabled by the coupled action of the enzymes glutamate synthetase (glutamine: 2 oxoglutarate amido-transferase [GOGAT]) and glutamine synthetase (GS) (Ka-meya et al, 2006, 2007).
Previous studies have demonstrated that oxidative processes often result in changes of the activities of key enzymes, including glutamine synthetase (GS), creatine kinase (CK) and tyrosine hydroxylase (Hensley et al., 1995).
Sequence analysis of the chloroplast glutamine synthetase gene, a single-copy nuclear gene, was used to infer relationship between the Rhodiola species.
United States Patent 7,070,945, "Process for determining the presence of monomeric brain associated human glutamine synthetase in patients exhibiting mild cognitive impairment," claims a method for determining those patients suffering from mild cognitive impairment who have a likelihood of progressing to Alzheimers disease.
The only way to eliminate any ammonia that has reached the brain cells is through a reaction mediated by an enzyme called glutamine synthetase, which combines a molecule of the amino acid glutamate with a molecule of ammonia to form the amino acid glutamine.

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