Pivotal role of glutamine synthetase in ammonia detoxification

Astrocyte glutamine synthetase: pivotal in health and disease.

The multifunctional properties of astrocytes signify their importance in brain physiology and neurological function. In addition to defining the brain architecture, astrocytes are primary elements of brain ion, pH and neurotransmitter homoeostasis. GS (glutamine synthetase), which catalyses the ATP-dependent condensation of ammonia and glutamate to form glutamine, is an enzyme particularly foun...

Glutamine versus Ammonia Utilization in the NAD Synthetase Family

NAD is a ubiquitous and essential metabolic redox cofactor which also functions as a substrate in certain regulatory pathways. The last step of NAD synthesis is the ATP-dependent amidation of deamido-NAD by NAD synthetase (NADS). Members of the NADS family are present in nearly all species across the three kingdoms of Life. In eukaryotic NADS, the core synthetase domain is fused with a nitrilas...

Regulation of synthesis of glutamine synthetase by adenylylated glutamine synthetase.

We have examined three mutants of Klebsiella aerogenes whose genetic lesions (glnB, glnD, and glnE) are in loci unlinked to the structural gene for glutamine sythetase (glnA) and in which the control of both the level and state of adenylylation of glutamine synthetase is altered. Each mutation alters a different component of the adenylylation system of glutamine synthetase [L-glutamate:ammonia ...

Ammonia and brain glutamine: inhibition of glutamine degradation by ammonia.

(the concentration used for radioautography), the uptake was mainly into the inner retina. However, as the exogenous taurine concentration was decreased to > 1 p~ the percentage of label accumulated by the photoreceptor layer increased with respect to the total uptake (Table 1). Further studies were carried out with the use of lOmin incubations and exposing the retinas to exogenous taurine conc...

Biochemical and molecular analysis of glutamine synthetase gene in brassica napus L.