Editing Glutamine (section)

== Functions ==
Glutamine plays a role in a variety of biochemical functions:
* Protein synthesis, as any other of the 20 [[proteinogenic amino acid]]s
* Lipid synthesis, especially by [[cancer]] cells.<ref name="pmid26001655">{{cite journal | vauthors = Corbet C, Feron O | title = Metabolic and mind shifts: from glucose to glutamine and acetate addictions in cancer | journal = Current Opinion in Clinical Nutrition and Metabolic Care | volume = 18 | issue = 4 | pages = 346–353 | date = July 2015 | pmid = 26001655 | doi = 10.1097/MCO.0000000000000178 | s2cid = 1478014 | veditors = Corbet C, Feron O }}</ref>
* Regulation of acid-base balance in the kidney by producing [[ammonium]]<ref>{{cite book | vauthors = Hall JE, Guyton AC |title=Textbook of Medical Physiology |edition = 11th |publisher=Elsevier Saunders |location=St. Louis, Mo |year=2006 |page=393 |isbn=978-0-7216-0240-0}}</ref>
* [[Glutaminolysis|Cellular energy]], as a source, next to [[glucose]]<ref>{{cite journal | vauthors = Aledo JC | title = Glutamine breakdown in rapidly dividing cells: waste or investment? | journal = BioEssays | volume = 26 | issue = 7 | pages = 778–785 | date = July 2004 | pmid = 15221859 | doi = 10.1002/bies.20063 }}</ref>
* [[Nitrogen]] donation for many [[anabolism|anabolic processes]], including the synthesis of [[purine metabolism|purines]]<ref name="Brosnan"/>
* Carbon donation, as a source, refilling the [[citric acid cycle]]<ref name="Yuneva">{{cite journal | vauthors = Yuneva M, Zamboni N, Oefner P, Sachidanandam R, Lazebnik Y | title = Deficiency in glutamine but not glucose induces MYC-dependent apoptosis in human cells | journal = The Journal of Cell Biology | volume = 178 | issue = 1 | pages = 93–105 | date = July 2007 | pmid = 17606868 | pmc = 2064426 | doi = 10.1083/jcb.200703099 }}</ref>
* Nontoxic transporter of [[ammonia]] in the blood circulation.<ref>{{cite journal | vauthors = Zielińska M, Albrecht J, Popek M | title = Dysregulation of Astrocytic Glutamine Transport in Acute Hyperammonemic Brain Edema | journal = Frontiers in Neuroscience | volume = 16 | pages = 874750 | date = 2022 | pmid = 35733937 | pmc = 9207324 | doi = 10.3389/fnins.2022.874750 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Dabrowska K, Skowronska K, Popek M, Obara-Michlewska M, Albrecht J, Zielinska M | title = Roles of Glutamate and Glutamine Transport in Ammonia Neurotoxicity: State of the Art and Question Marks | journal = Endocrine, Metabolic & Immune Disorders Drug Targets | volume = 18 | issue = 4 | pages = 306–315 | date = 2018 | pmid = 29256360 | doi = 10.2174/1871520618666171219124427 | s2cid = 26569656 }}</ref>

=== Roles in metabolism ===
Glutamine maintains redox balance by participating in [[glutathione]] synthesis and contributing to anabolic processes such as lipid synthesis by reductive carboxylation.<ref>{{cite journal | vauthors = Jiang L, Shestov AA, Swain P, Yang C, Parker SJ, Wang QA, Terada LS, Adams ND, McCabe MT, Pietrak B, Schmidt S, Metallo CM, Dranka BP, Schwartz B, DeBerardinis RJ | title = Reductive carboxylation supports redox homeostasis during anchorage-independent growth | journal = Nature | volume = 532 | issue = 7598 | pages = 255–258 | date = April 2016 | pmid = 27049945 | doi = 10.1038/nature17393 | pmc = 4860952 | bibcode = 2016Natur.532..255J }}</ref>

Glutamine provides a source of carbon and nitrogen for use in other metabolic processes. Glutamine is present in serum at higher concentrations than other amino acids<ref>{{cite journal | vauthors = Welbourne TC | title = Ammonia production and glutamine incorporation into glutathione in the functioning rat kidney | journal = Canadian Journal of Biochemistry | volume = 57 | issue = 3 | pages = 233–237 | date = March 1979 | pmid = 436006 | doi = 10.1139/o79-029 }}</ref> and is essential for many cellular functions. Examples include the synthesis of [[nucleotide]]s and [[non-essential amino acid]]s.<ref>{{cite journal | vauthors = DeBerardinis RJ, Mancuso A, Daikhin E, Nissim I, Yudkoff M, Wehrli S, Thompson CB | title = Beyond aerobic glycolysis: transformed cells can engage in glutamine metabolism that exceeds the requirement for protein and nucleotide synthesis | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 104 | issue = 49 | pages = 19345–19350 | date = December 2007 | pmid = 18032601 | doi = 10.1073/pnas.0709747104 | pmc = 2148292 | bibcode = 2007PNAS..10419345D | doi-access = free }}</ref> One of the most important functions of glutamine is its ability to be converted into α-KG, which helps to maintain the flow of the tricarboxylic acid cycle, generating ATP via the electron carriers NADH and FADH<sub>2</sub>.<ref>{{cite journal | vauthors = DeBerardinis RJ, Lum JJ, Hatzivassiliou G, Thompson CB | title = The biology of cancer: metabolic reprogramming fuels cell growth and proliferation | language = English | journal = Cell Metabolism | volume = 7 | issue = 1 | pages = 11–20 | date = January 2008 | pmid = 18177721 | doi = 10.1016/j.cmet.2007.10.002 | doi-access = free }}</ref> The highest consumption of glutamine occurs in the cells of the intestines,<ref name="Brosnan"/> kidney cells  (where it is used for acid-base balance), activated immune cells,<ref>{{cite journal | vauthors = Newsholme P | title = Why is L-glutamine metabolism important to cells of the immune system in health, postinjury, surgery or infection? | journal = The Journal of Nutrition | volume = 131 | issue = 9 Suppl | pages = 2515S–2522S; discussion 2522S–4S | date = September 2001 | pmid = 11533304 | doi = 10.1093/jn/131.9.2515S | doi-access = free }}</ref> and many [[cancer]] cells.<ref name="pmid26001655"/><ref name="Yuneva"/><ref>{{cite journal | vauthors = Fernandez-de-Cossio-Diaz J, Vazquez A | title = Limits of aerobic metabolism in cancer cells | language = En | journal = Scientific Reports | volume = 7 | issue = 1 | pages = 13488 | date = October 2017 | pmid = 29044214 | pmc = 5647437 | doi = 10.1038/s41598-017-14071-y | bibcode = 2017NatSR...713488F }}</ref>