32 by: Ayushi Patel
Student –Ayushi Patel
Enzyme Name: GLUTAMINE SYNTHETASE
E. C. Number: 6.3.1.2
Where is the enzyme found? Glutamine synthetase is found across various organisms, including bacteria, plants, and animals, where it plays a crucial role in nitrogen metabolism. In humans, it is present in the liver, brain, and kidneys, aiding in ammonia detoxification, neurotransmitter regulation, and acid-base homeostasis. In plants, it is located in chloroplasts, where it incorporates ammonia produced during photorespiration and nitrogen fixation into organic compounds. In bacteria, such as E. coli, it helps assimilate nitrogen under low nitrogen conditions. Across all systems, glutamine synthetase prevents ammonia toxicity by converting it into glutamine, an essential molecule for nitrogen balance.
What does the enzyme do? Glutamine synthetase catalyzes the ATP-dependent condensation of glutamate and ammonium (NH₄⁺) to form glutamine. This reaction is essential for nitrogen metabolism, as it helps in the assimilation of toxic ammonium into glutamine, a less toxic compound. Glutamine serves as a nitrogen donor in various biosynthetic processes, including the synthesis of nucleotides and amino acids, and is also involved in the transport of nitrogen between tissues.
Any other interesting facts or important information on glutamine synthetase enzyme:
- Evolutionary Importance: Glutamine synthetase is one of the most highly regulated enzymes in the cell, reflecting its importance in maintaining nitrogen balance.
- Medical Relevance: Mutations or misregulation of glutamine synthetase can result in serious neurological diseases due to ammonia toxicity.
- Structural Insights: The enzyme often forms a dodecameric structure (12 subunits), arranged in two hexameric rings, which is crucial for its function and regulation.
- Industrial and Biotechnological Uses: In biotechnology, glutamine synthetase is used in the production of glutamine supplements and in fermentation processes to enhance nitrogen incorporation, making it a valuable tool in the food and pharmaceutical industries.
These facts highlight the enzyme’s importance not only in basic biological processes but also in medical and industrial applications.
References
- Frieg, B., Görg, B., Qvartskhava, N., Jeitner, T., Homeyer, N., Häussinger, D., & Gohlke, H. (2020). Mechanism of Fully Reversible, pH-Sensitive Inhibition of Human Glutamine Synthetase by Tyrosine Nitration. Journal of Chemical Theory and Computation, 16(7), 4694–4705. https://doi.org/10.1021/acs.jctc.0c00249
- Fortunato, S., Nigro, D., Lasorella, C., Marcotuli, I., Gadaleta, A., & de Pinto, M. C. (2023). The Role of Glutamine Synthetase (GS) and Glutamate Synthase (GOGAT) in the Improvement of Nitrogen Use Efficiency in Cereals. Biomolecules (2218-273X), 13(12), 1771. https://doi.org/10.3390/biom13121771
- Caredio, D., Koderman, M., Frontzek, K. J., Sorce, S., Nuvolone, M., Bremer, J., Mariutti, G., Schwarz, P., Madrigal, L., Mitrovic, M., Sellitto, S., Streichenberger, N., Scheckel, C., & Aguzzi, A. (2024). Prion diseases disrupt glutamate/glutamine metabolism in skeletal muscle. PLoS Pathogens, 20(9), 1–26. https://doi.org/10.1371/journal.ppat.1012552
- Chemistry LibreTexts. (n.d.). Glutamine synthetase. https://chem.libretexts.org/Courses/Saint_Marys_College_Notre_Dame_IN/CHEM_342%3A_Bioinorganic_Chemistry/Readings/Metals_in_Biological_Systems_(Saint_Mary’s_College)/Glutamine_Synthetase
- Goodsell, D. Glutamine Synthetase http://pdb101.rcsb.org/motm/30
- Glutamine synthetase, a third cation binding site. Protein Science,4, 2358-2365. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2143006/pdf/8563633.pdf.
