Editing Glutamine

{{Redirect|Gln||GLN (disambiguation)}}
{{Distinguish|Glutamic acid|Glutaric acid}}
{{Use dmy dates|date=March 2018}}
{{cs1 config|name-list-style=vanc|display-authors=6}}
{{chembox
| ImageFile      = L-Glutamin - L-Glutamine.svg
| ImageClass     = skin-invert-image
| ImageCaption   = [[Skeletal formula]] of <small>L</small>-glutamine
| ImageFileL2    = Glutamine-from-xtal-3D-bs-17.png
| ImageClassL2   = bg-transparent
| ImageSizeL2    = 115
| ImageCaptionL2 = [[Ball-and-stick model]]
| ImageFileR2    = Glutamine-from-xtal-3D-sf.png
| ImageClassR2   = bg-transparent
| ImageSizeR2    = 110
| ImageCaptionR2 = [[Space-filling model]]
| ImageFile3     = Sample of L-Glutamine.jpg
| IUPACName      = Glutamine
| OtherNames     = L-Glutamine <br> (levo)glutamide <br> 2,5-Diamino-5-oxopentanoic acid <br>2-Amino-4-carbamoylbutanoic acid<br>Endari<ref name="FDA2017Glu"/>
| SystematicName = 2-Amino-4-carbamoylbutanoic acid
| Section1       = {{Chembox Identifiers
| Abbreviations = '''Gln''', '''Q'''
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = 0RH81L854J
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 930
| DrugBank_Ref = {{drugbankcite|correct|drugbank}}
| DrugBank = DB00130
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = C00303
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C5H10N2O3/c6-3(5(9)10)1-2-4(7)8/h3H,1-2,6H2,(H2,7,8)(H,9,10)/t3-/m0/s1
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = ZDXPYRJPNDTMRX-VKHMYHEASA-N
| CASNo = 56-85-9
| CASNo_Ref = {{cascite|correct|CAS}}
| EC_number = 200-292-1
| PubChem = 5961
| IUPHAR_ligand = 723
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 5746
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 18050
| SMILES = O=C(N)CCC(N)C(=O)O
| SMILES1 = O=C(N)CCC([NH3+])C(=O)[O-]
| SMILES1_Comment = [[Zwitterion]]
}}
| Section2       = {{Chembox Properties
| Properties_ref = <ref>{{RubberBible62nd|page=C-311}}.</ref>
| C=5 | H=10 | N=2 | O=3
| Appearance =
| Density =
| MeltingPt = decomposes around 185°C
| Solubility = soluble
| SpecRotation = +6.5º (H<sub>2</sub>O, ''c'' = 2)
| pKa=2.2 (carboxyl), 9.1 (amino)
  }}
| Section6       = {{Chembox Pharmacology
| ATCCode_prefix = A16
| ATCCode_suffix = AA03
}}
| Section7       = {{Chembox Hazards
| FlashPt =
| AutoignitionPt =
  }}
}}
{{Infobox drug
| drug_name         = L-glutamine oral powder
| INN               =
| type              = <!-- empty -->
| image             =
| width             =
| alt               =
| caption           =

<!-- Clinical data -->
| pronounce         =
| tradename         = Endari, Nutrestore
| Drugs.com         = {{drugs.com|monograph|l-glutamine}}
| MedlinePlus       = a617035
| DailyMedID        = Glutamine
| pregnancy_AU      = <!-- A / B1 / B2 / B3 / C / D / X -->
| pregnancy_AU_comment =
| pregnancy_category=
| routes_of_administration = [[By mouth]]
| class             = [[Gastrointestinal agent]]
| ATCvet            =
| ATC_prefix        = A16
| ATC_suffix        = AA03
| ATC_supplemental  =

<!-- Legal status -->
| legal_AU = <!-- S2, S3, S4, S5, S6, S7, S8, S9 or Unscheduled-->
| legal_AU_comment =
| legal_BR =  <!-- OTC, A1, A2, A3, B1, B2, C1, C2, C3, C4, C5, D1, D2, E, F-->
| legal_BR_comment =
| legal_CA = <!-- OTC, Rx-only, Schedule I, II, III, IV, V, VI, VII, VIII -->
| legal_CA_comment =
| legal_DE = <!-- Anlage I, II, III or Unscheduled-->
| legal_DE_comment =
| legal_NZ = <!-- Class A, B, C -->
| legal_NZ_comment =
| legal_UK = <!-- GSL, P, POM, CD, CD Lic, CD POM, CD No Reg POM, CD (Benz) POM, CD (Anab) POM or CD Inv POM / Class A, B, C -->
| legal_UK_comment =
| legal_US = Rx-only
| legal_US_comment =
| legal_UN = <!-- N I, II, III, IV / P I, II, III, IV-->
| legal_UN_comment =
| legal_status      = <!-- For countries not listed above -->

<!-- Pharmacokinetic data -->
| bioavailability   =
| protein_bound     =
| metabolism        =
| metabolites       =
| onset             =
| elimination_half-life =
| duration_of_action =
| excretion         =

<!-- Identifiers -->
| CAS_number_Ref    =
| CAS_number        = 56-85-9
| CAS_supplemental  =
| PubChem           = 5961
| PubChemSubstance  =
| IUPHAR_ligand     =
| DrugBank_Ref      =
| DrugBank          = DB00130
| ChemSpiderID_Ref  =
| ChemSpiderID      = 5746
| UNII_Ref          =
| UNII              = 0RH81L854J
| KEGG_Ref          =
| KEGG              = D00015
| KEGG2_Ref         =
| KEGG2             = C00064
| ChEBI_Ref         =
| ChEBI             = 58359
| ChEMBL_Ref        =
| ChEMBL            = 930
| NIAID_ChemDB      =
| PDB_ligand        = GLN
| synonyms          =

<!-- Chemical and physical data -->
| IUPAC_name        = (S)-2,5-diamino-5-oxopentanoic acid
| chemical_formula  =
| C=5 | H=10 | N=2 | O=3
| SMILES            = C(CC(=O)N)C(C(=O)O)N
| Jmol              =
| StdInChI          = 1S/C5H10N2O3/c6-3(5(9)10)1-2-4(7)8/h3H,1-2,6H2,(H2,7,8)(H,9,10)/t3-/m0/s1
| StdInChI_comment  =
| StdInChIKey       = ZDXPYRJPNDTMRX-VKHMYHEASA-N
| density           =
| density_notes     =
| melting_point     =
| melting_high      =
| melting_notes     =
| boiling_point     =
| boiling_notes     =
| solubility        =
| sol_units         =
| specific_rotation =
}}
[[File:Glutamine-spin.gif|thumb|Glutamine ball and stick model spinning]]
'''Glutamine''' (symbol '''Gln''' or '''Q''')<ref>{{cite web | url = http://www.chem.qmul.ac.uk/iupac/AminoAcid/AA1n2.html | title = Nomenclature and Symbolism for Amino Acids and Peptides | publisher = IUPAC-IUB Joint Commission on Biochemical Nomenclature | year = 1983 | access-date = 5 March 2018 | archive-url = https://web.archive.org/web/20081009023202/http://www.chem.qmul.ac.uk/iupac/AminoAcid/AA1n2.html | archive-date = 9 October 2008 | url-status = dead }}</ref> is an [[amino acid|α-amino acid]] that is used in the biosynthesis of [[protein]]s.  Its [[side chain]] is similar to that of [[glutamic acid]], except the carboxylic acid group is replaced by an [[amide]]. It is classified as a charge-neutral, polar amino acid.  It is non-essential and [[Essential amino acid|conditionally essential]] in humans, meaning the body can usually [[Biosynthesis|synthesize]] sufficient amounts of it, but in some instances of stress, the body's demand for glutamine increases, and glutamine must be obtained from the diet.<ref>{{cite book | veditors = Otten JJ, Hellwig JP, Meyers LD | author = Food and Nutrition Board of the Institute of Medicine | chapter = Protein and Amino Acids |title=Dietary Reference Intakes: The Essential Guide to Nutrient Requirements |date=2006 |publisher=National Academies Press |location=Washington, D.C. | page = 147 |isbn=978-0-309-10091-5 | url = http://www.nal.usda.gov/fnic/DRI/Essential_Guide/DRIEssentialGuideNutReq.pdf | archive-url = https://web.archive.org/web/20140309020936/http://www.nal.usda.gov/fnic/DRI/Essential_Guide/DRIEssentialGuideNutReq.pdf | archive-date = 9 March 2014 }}</ref><ref>{{cite journal | vauthors = Lacey JM, Wilmore DW | title = Is glutamine a conditionally essential amino acid? | journal = Nutrition Reviews | volume = 48 | issue = 8 | pages = 297–309 | date = August 1990 | pmid = 2080048 | doi = 10.1111/j.1753-4887.1990.tb02967.x }}</ref> It is [[Genetic code|encoded]] by the [[codons]] CAA and CAG. It is named after glutamic acid, which in turn is named after its discovery in cereal proteins, [[gluten]].<ref name = "Saffran_1998">{{Cite journal | vauthors = Saffran M |date=April 1998 |title=Amino acid names and parlor games: from trivial names to a one-letter code, amino acid names have strained students' memories. Is a more rational nomenclature possible? |journal=Biochemical Education |volume=26 |issue=2 |pages=116–118 |doi=10.1016/s0307-4412(97)00167-2 |issn=0307-4412}}</ref>

In [[human blood]], glutamine is the most abundant free [[amino acid]].<ref name="Brosnan">{{cite journal | vauthors = Brosnan JT | title = Interorgan amino acid transport and its regulation | journal = The Journal of Nutrition | volume = 133 | issue = 6 Suppl 1 | pages = 2068S–2072S | date = June 2003 | pmid = 12771367 | doi = 10.1093/jn/133.6.2068S | doi-access = free }}{{open access}}</ref>

The dietary sources of glutamine include especially the protein-rich foods like [[beef]], [[Chicken (food)|chicken]], [[Fish as food|fish]], [[dairy products]], [[Egg as food|eggs]], [[vegetables]] like [[bean]]s, [[beet]]s, [[cabbage]], [[spinach]], [[carrots]], [[parsley]], [[vegetable juice]]s and also in [[wheat]], [[papaya]], [[Brussels sprout]]s, [[celery]], [[kale]] and [[fermented food]]s like [[miso]].

The one-letter symbol Q for glutamine was assigned in alphabetical sequence to N for [[asparagine]], being larger by merely one [[Methylene group|methylene]] –CH2– group. Note that P was used for proline, and O was avoided due to similarity with D. The mnemonic ''Q''lutamine was also proposed.<ref name = "Saffran_1998" />

== 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>

==Production==
Glutamine is produced industrially using mutants of ''[[Brevibacterium flavum]]'', which gives ca. 40 g/L in 2 days using [[glucose]] as a carbon source.<ref>{{Ullmann| vauthors = Drauz K, Grayson I, Kleemann A, Krimmer HP, Leuchtenberger W, Weckbecker C |year=2007|title=Amino Acids|doi=10.1002/14356007.a02_057.pub2}}</ref>

===Biosynthesis===
Glutamine synthesis from [[glutamate]] and ammonia is catalyzed by the [[enzyme]] [[glutamine synthetase]]. The majority of glutamine production occurs in muscle tissue, accounting for about 90% of all glutamine synthesized. Glutamine is also released, in small amounts, by the lungs and brain.<ref>{{cite journal | vauthors = Newsholme P, Lima MM, Procopio J, Pithon-Curi TC, Doi SQ, Bazotte RB, Curi R | title = Glutamine and glutamate as vital metabolites | journal = Brazilian Journal of Medical and Biological Research = Revista Brasileira de Pesquisas Medicas e Biologicas | volume = 36 | issue = 2 | pages = 153–163 | date = February 2003 | pmid = 12563517 | doi = 10.1590/S0100-879X2003000200002 | doi-access = free }}</ref> Although the liver is capable of  glutamine synthesis, its role in glutamine metabolism is more regulatory than productive, as the liver takes up glutamine derived from the gut via the [[hepatic portal system]].<ref name="Brosnan"/>

== Uses ==
=== Nutrition ===
Glutamine is the most abundant naturally occurring, [[essential amino acid|nonessential amino acid]] in the human body, and one of the few amino acids that can directly cross the [[blood–brain barrier]].<ref name="Brosnan"/> Humans obtain glutamine through [[catabolism]] of [[protein]]s in foods they eat.<ref name=Watford2015rev>{{cite journal | vauthors = Watford M | title = Glutamine and glutamate: Nonessential or essential amino acids? | journal = Animal Nutrition | volume = 1 | issue = 3 | pages = 119–122 | date = September 2015 | pmid = 29767158 | pmc = 5945979 | doi = 10.1016/j.aninu.2015.08.008 }}</ref> In states where tissue is being built or repaired, like growth of babies, or healing from wounds or severe illness, glutamine becomes [[Conditionally essential amino acid|conditionally essential]].<ref name=Watford2015rev/>

=== Sickle cell disease ===
{{missing information|section|(possible) mechanism of action, pharmacokinetics in {{PMID|31985279}}|date=November 2023}}
In 2017, the U.S. [[Food and Drug Administration]] (FDA) approved <small>L</small>-glutamine oral powder, marketed as '''Endari''', to reduce severe complications of [[sickle cell disease]] in people aged five years and older with the disorder.<ref name="FDA2017Glu">{{cite press release|title=FDA approves new treatment for sickle cell disease|url=https://www.fda.gov/news-events/press-announcements/fda-approves-new-treatment-sickle-cell-disease |website=U.S. [[Food and Drug Administration]] (FDA)|access-date=10 July 2017|date=7 July 2017}} {{PD-notice}}</ref>

The safety and efficacy of L-glutamine oral powder were studied in a randomized trial of subjects ages five to 58 years old with sickle cell disease who had two or more painful crises within the 12 months prior to enrollment in the trial.<ref name="FDA2017Glu" /> Subjects were assigned randomly to treatment with L-glutamine oral powder or placebo, and the effect of treatment was evaluated over 48 weeks.<ref name="FDA2017Glu" /> Subjects who were treated with L-glutamine oral powder experienced fewer hospital visits for pain treated with a parenterally administered narcotic or ketorolac (sickle cell crises), on average, compared to subjects who received a placebo (median 3 vs. median 4), fewer hospitalizations for sickle cell pain (median 2 vs. median 3), and fewer days in the hospital (median 6.5 days vs. median 11 days).<ref name="FDA2017Glu" />  Subjects who received L-glutamine oral powder also had fewer occurrences of acute chest syndrome (a life-threatening complication of sickle cell disease) compared with patients who received a placebo (8.6 percent vs. 23.1 percent).<ref name="FDA2017Glu" />

Common side effects of L-glutamine oral powder include constipation, nausea, headache, abdominal pain, cough, pain in the extremities, back pain and chest pain.<ref name="FDA2017Glu" />

L-glutamine oral powder received [[orphan drug]] designation.<ref name="FDA2017Glu" /> The FDA granted the approval of Endari to Emmaus Medical Inc.<ref name="FDA2017Glu" />

=== Medical food ===
Glutamine is marketed as [[medical food]] and is prescribed when a medical professional believes a person in their care needs supplementary glutamine due to metabolic demands beyond what can be met by endogenous synthesis or diet.<ref>{{cite web|title=GlutaSolve, NutreStore, SYMPT-X G.I., SYMPT-X Glutamine (glutamine) Drug Side Effects, Interactions, and Medication Information on eMedicineHealth.|url=http://www.emedicinehealth.com/drug-glutamine/article_em.htm|website=eMedicineHealth|access-date=24 January 2017}}</ref>

== Safety ==
Glutamine is safe in adults and in preterm infants.<ref name="pmid11533313">{{cite journal | vauthors = Garlick PJ | title = Assessment of the safety of glutamine and other amino acids | journal = The Journal of Nutrition | volume = 131 | issue = 9 Suppl | pages = 2556S–2561S | date = September 2001 | pmid = 11533313 | doi = 10.1093/jn/131.9.2556S | doi-access = free }}</ref> Although glutamine is metabolized to glutamate and ammonia, both of which have neurological effects, their concentrations are not increased much, and no adverse neurological effects were detected.<ref name="pmid11533313"/> The observed safe level for supplemental <small>L</small>-glutamine in normal healthy adults is 14 g/day.<ref name="pmid18325648">{{cite journal | vauthors = Shao A, Hathcock JN | title = Risk assessment for the amino acids taurine, L-glutamine and L-arginine | journal = Regulatory Toxicology and Pharmacology | volume = 50 | issue = 3 | pages = 376–399 | date = April 2008 | pmid = 18325648 | doi = 10.1016/j.yrtph.2008.01.004 }}</ref>

Adverse effects of glutamine have been described for people receiving home parenteral nutrition and those with liver-function abnormalities.<ref name="pmid11451714">{{cite journal | vauthors = Buchman AL | title = Glutamine: commercially essential or conditionally essential? A critical appraisal of the human data | journal = The American Journal of Clinical Nutrition | volume = 74 | issue = 1 | pages = 25–32 | date = July 2001 | pmid = 11451714 | doi = 10.1093/ajcn/74.1.25 | doi-access = free }}</ref>
Although glutamine has no effect on the proliferation of tumor cells, it is still possible that glutamine supplementation may be detrimental in some cancer types.<ref name="pmid22990615">{{cite journal | vauthors = Holecek M | title = Side effects of long-term glutamine supplementation | journal = Journal of Parenteral and Enteral Nutrition | volume = 37 | issue = 5 | pages = 607–616 | date = September 2013 | pmid = 22990615 | doi = 10.1177/0148607112460682 }}</ref>

Ceasing glutamine supplementation in people adapted to very high consumption may initiate a withdrawal effect, raising the risk of health problems such as infections or impaired integrity of the intestine.<ref name="pmid22990615"/>

== Structure ==
Glutamine can exist in either of two [[enantiomer]]ic forms, <small>L</small>-glutamine and <small>D</small>-glutamine.  The <small>L</small>-form is found in nature.  Glutamine contains an α-amino group which is in the protonated −NH<sub>3</sub><sup>+</sup> form under biological conditions and a carboxylic acid group which is in the deprotonated −COO<sup>−</sup> form, known as carboxylate, under physiological conditions.
[[File:Betain-Glutamin.png|class=skin-invert-image|thumb|left|250px|Glutamine [[zwitterionic]] forms at neutral pH: L-glutamine (left) and D-glutamine]]
{{clear left}}

==Research==
[[File:BMRI2015-545467.001-upscaled.webp|class=skin-invert-image|thumb|right|upright=1.5|Consequences of glutamine depletion in critically ill individuals<ref name="pmid26495301">{{cite journal | vauthors = Stehle P, Kuhn KS | title = Glutamine: an obligatory parenteral nutrition substrate in critical care therapy | journal = BioMed Research International | volume = 2015 | pages = 545467 | year = 2015 | pmid = 26495301 | pmc = 4606408 | doi = 10.1155/2015/545467 | doi-access = free }}</ref>]]

Glutamine supplementation was investigated for its possible effects in critically ill people or after abdominal surgery, but the low quality of research prevented conclusions about any effect.<ref>{{cite journal | vauthors = Tao KM, Li XQ, Yang LQ, Yu WF, Lu ZJ, Sun YM, Wu FX | title = Glutamine supplementation for critically ill adults | journal = The Cochrane Database of Systematic Reviews | issue = 9 | pages = CD010050 | date = September 2014 | volume = 2018 | pmid = 25199493 | pmc = 6517119 | doi = 10.1002/14651858.CD010050.pub2 }}</ref> Supplementation does not appear to have an effect in infants with significant stomach or intestinal disorders.<ref>{{cite journal | vauthors = Moe-Byrne T, Brown JV, McGuire W | title = Glutamine supplementation to prevent morbidity and mortality in preterm infants | journal = The Cochrane Database of Systematic Reviews | volume = 4 | pages = CD001457 | date = April 2016 | issue = 4 | pmid = 27089158 | pmc = 7055588 | doi = 10.1002/14651858.CD001457.pub6 | veditors = McGuire W }}</ref>

== See also ==
* [[Isoglutamine]]
* [[Trinucleotide repeat disorder]]
* [[PolyQ tract]]

== References ==
{{reflist}}

== External links ==
* [http://gmd.mpimp-golm.mpg.de/Spectrums/c1bca564-a7ee-4401-85f8-4a3f74dce29c.aspx Glutamine spectra] acquired through [[mass spectroscopy]]

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