31 by: Zippa Kaonga
Student – Ziipa Kaonga
Enzyme – Glutamine Synthetase
EC # – 6.3.1.2
Where is the enzyme Found? Glutamine synthetase is a cytosolic enzyme found in every living organism on Earth, in the cytoplasm of most every cell. In humans, glutamine synthetase is found in abundance in the brain, liver, kidneys and muscles. It is predominantly in astrocyte neurons of the brain and keratinocytes of the human skin.
What does it do? Glutamine synthetase mainly helps maintain the organism’s ammonium levels by fixing it into a useful and versatile amino acid. Also known as glutamate-ammonia ligase, glutamine synthetase does this via an ATP dependant ligation of glutamate and ammonia. This ligating action is crucial in detoxifying ammonia, a potentially harmful byproduct of amino acid metabolism, and regulating nitrogen levels in cells. The biosynthesis of glutamine through this process supports various physiological functions, including protein synthesis, neurotransmitter regulation, and cellular energy management.
Interesting facts – The shape of glutamine synthetase reminds me of a Tim Horton’s honey crueller donut. It has also been targeted in tumors as a treatment for cancer as it has been found that doing so disrupts their growth.
References
- Adeva MM, Souto G, Blanco N, Donapetry C. 2012. Ammonium metabolism in humans. Metabolism. 61(11):1495–1511. [accessed 2024 Sep 23] https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/glutamine-synthetase doi:https://doi.org/10.1016/j.metabol.2012.07.007.
- Eisenberg D, Gill HS, Pfluegl GMU, Rotstein SH. 2000. Structure–function relationships of glutamine synthetases. Biochimica et Biophysica Acta (BBA) – Protein Structure and Molecular Enzymology. 1477(1-2):122–145. doi:https://doi.org/10.1016/s0167-4838(99)00270-8.
- Yang L, Achreja A, Yeung T-L, Mangala Lingegowda S, Jiang D, Han C, Baddour J, Marini Juan C, Ni J, Nakahara R, et al. 2016. Targeting Stromal Glutamine Synthetase in Tumors Disrupts Tumor Microenvironment-Regulated Cancer Cell Growth. Cell Metabolism. 24(5):685–700. [accessed 2024 Sep 23] https://www.sciencedirect.com/science/article/pii/S1550413116305423#:~:text=Using%20an%20orthotopic%20mouse%20model,simultaneously%20for%20desirable%20therapeutic%20outcomes. doi:https://doi.org/10.1016/j.cmet.2016.10.011.
