Related Experiment Video
Updated: Aug 11, 2026

Glutamine Flux Imaging Using Genetically Encoded Sensors
Published on: July 31, 2014
beta-Glutamate as a substrate for glutamine synthetase
P Robinson1, K Neelon, H J Schreier
1Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, USA.
Abstract:
The conversion of beta-glutamate to beta-glutamine by archaeal and bacterial glutamine synthetase (GS) enzymes has been examined. The GS from Methanohalophilus portucalensis (which was partially purified) is capable of catalyzing the amidation of this substrate with a rate sevenfold less than the rate obtained with alpha-glutamate. Recombinant GS from the archaea Methanococcus jannaschii and Archaeoglobus fulgidus were considerably more selective for alpha-glutamate than beta-glutamate as a substrate. All the archaeal enzymes were much less selective than the two bacterial GS (from Escherichia coli and Bacillus subtilis), whose specific activities towards beta-glutamate were much smaller than rates with the alpha-isomer. These results are discussed in light of the observation that beta-glutamate is accumulated as an osmolyte in many archaea while beta-glutamine (produced by glutamine synthetase) is used as an osmolyte only in M. portucalensis.
More Related Videos
08:01LERLIC-MS/MS for In-depth Characterization and Quantification of Glutamine and Asparagine Deamidation in Shotgun Proteomics
Published on: April 9, 2017
08:37Assessment of Glutamine as a Fuel Source for Alveolar Macrophages Exposed to Chronic Ethanol Using an Extracellular Flux Bioanalyzer
Published on: November 15, 2024
Related Concept Videos
tRNA Activation
Allosteric Proteins-ATCase
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Phase II Reactions: Glutathione Conjugation and Mercapturic Acid Formation
Several distinctive characteristics distinguish glutathione conjugation from other phase II...
Inorganic Nitrogen Assimilation
Amino Acid Biosynthetic Pathways
Biosynthesis of Nucleic Acids