Glutamine

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"Gln" redirects here. For other uses, see GLN (disambiguation).
Glutamine
L-Glutamin - L-Glutamine.svg
L-Glutamine
Sample of L-Glutamine.jpg
Names
IUPAC name
Glutamine
Other names
L-Glutamine
(levo)glutamide
2-Amino-4-carbamoylbutanoic acid
Identifiers
56-85-9 YesY
3D model (Jmol) Interactive image
Abbreviations Gln, Q
ChEBI CHEBI:28300 YesY
ChEMBL ChEMBL930 N
ChemSpider 718 YesY
ECHA InfoCard 100.000.266
EC Number 200-292-1
723
KEGG C00303 YesY
PubChem 738
UNII 0RH81L854J YesY
Properties[1]
C5H10N2O3
Molar mass 146.15 g·mol−1
Melting point decomposes around 185°C
soluble
Acidity (pKa) 2.2 (carboxyl), 9.1 (amino)
+6.5º (H2O, c = 2)
Pharmacology
A16AA03 (WHO)
Supplementary data page
Refractive index (n),
Dielectric constantr), etc.
Thermodynamic
data
Phase behaviour
solid–liquid–gas
UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
Infobox references

Glutamine (abbreviated as Gln or Q; encoded by the codons CAA and CAG) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH3+ form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −COO form under biological conditions), and a side chain amide which replaces the side chain hydroxyl of glutamic acid with an amine functional group, classifying it as a charge neutral, polar (at physiological pH) amino acid. It is non-essential and conditionally essential in humans, meaning the body can usually 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.[2][3]

In human blood, glutamine is the most abundant free amino acid.[4]

Functions[edit]

Glutamine plays a role in a variety of biochemical functions:

On the level of tissue, glutamine plays a role in maintaining the normal integrity of the intestinal mucosa.[10]

Producing and consuming organs[edit]

Producers[edit]

Glutamine is synthesized by the enzyme glutamine synthetase from glutamate and ammonia. The most relevant glutamine-producing tissue is the muscle mass, accounting for about 90% of all glutamine synthesized. Glutamine is also released, in small amounts, by the lung and the brain.[11] Although the liver is capable of relevant glutamine synthesis, its role in glutamine metabolism is more regulatory than producing, since the liver takes up large amounts of glutamine derived from the gut.[4]

Consumers[edit]

The most eager consumers of glutamine are the cells of intestines,[4] the kidney cells for the acid-base balance, activated immune cells,[12] and many cancer cells.[5][6][9]

Structure[edit]

Glutamine zwitterionic forms at neutral pH: L-glutamine (left) and D-glutamine

Nutrition[edit]

Occurrences in nature[edit]

Glutamine is the most abundant naturally occurring, nonessential amino acid in the human body, and one of the few amino acids that can directly cross the blood–brain barrier.[4] In the body, it is found circulating in the blood, as well as stored in the skeletal muscles. It becomes conditionally essential (requiring intake from food or supplements) in states of illness or injury.[medical citation needed]

Dietary sources[edit]

Humans obtain glutamine through catabolism of proteins in foods they eat.[13]

Research[edit]

Consequences of glutamine depletion in critically ill individuals[14]

In states where tissue is being built or repaired, like growth of infants, or healing from traumtic wounds or severe illness, glutamine becomes conditionally essential.[13]

Glutamine mouthwash may be useful to prevent oral mucositis in people undergoing chemotherapy but intravenous glutamine does not appear useful to prevent mucositis in the GI tract.[15]

Glutamine supplementation was thought to have potential to reduce complications in people who are critically ill or who have had abdominal surgery but this was based on poor quality clinical trials;[16] a large randomized clinical trial found worse outcomes in the group that was given glutatmine.[17]

Supplementation does not appear to be useful in adults or children with Crohns disease or inflammatory bowel disease but clinical studies as of 2016 were underpowered.[10]

Supplementation does not appear to have an effect in infants with significant problems of the stomach or intestines.[18]

Medical food[edit]

Several brands of glutamine are marketed as medical food and is prescribed when a medical professional believes a person in their care needs supplementary glutamine due to loss or deficiency of glutamine.[19]

See also[edit]

References[edit]

  1. ^ Weast, Robert C., ed. (1981). CRC Handbook of Chemistry and Physics (62nd ed.). Boca Raton, FL: CRC Press. p. C-311. ISBN 0-8493-0462-8. .
  2. ^ Dietary Reference Intakes: The Essential Guide to Nutrient Requirements, published by the Institute of Medicine's Food and Nutrition Board, currently available online at http://fnic.nal.usda.gov/dietary-guidance/dietary-reference-intakes/dri-reports
  3. ^ Lacey, JM; Wilmore, DW (Aug 1990). "Is glutamine a conditionally essential amino acid?". Nutrition Reviews. 48 (8): 297–309. doi:10.1111/j.1753-4887.1990.tb02967.x. 
  4. ^ a b c d e Brosnan, John T. (June 2003). "Interorgan amino acid transport and its regulation". J. Nutr. 133 (6 Suppl 1): 2068S–2072S. PMID 12771367. open access publication - free to read
  5. ^ a b Corbet C, Feron O (2015). "Metabolic and mind shifts: from glucose to glutamine and acetate addictions in cancer". Current Opinion in Clinical Nutrition and Metabolic Care. 18 (4): 346–353. doi:10.1097/MCO.0000000000000178. PMID 26001655. 
  6. ^ a b Gouw AM, Toal GG, Felsher DW (2016). "Metabolic vulnerabilities of MYC-induced cancer". Oncotarget. doi:10.18632/oncotarget.7223. PMID 26863454. 
  7. ^ Hall, John E.; Guyton, Arthur C. (2006). Textbook of medical physiology (11th ed.). St. Louis, Mo: Elsevier Saunders. p. 393. ISBN 0-7216-0240-1. 
  8. ^ Aledo, J. C. (2004). "Glutamine breakdown in rapidly dividing cells: Waste or investment?". BioEssays. 26 (7): 778–785. doi:10.1002/bies.20063. PMID 15221859. 
  9. ^ a b Yuneva, M.; Zamboni, N.; Oefner, P.; Sachidanandam, R.; Lazebnik, Y. (2007). "Deficiency in glutamine but not glucose induces MYC-dependent apoptosis in human cells". The Journal of Cell Biology. 178 (1): 93–105. doi:10.1083/jcb.200703099. PMC 2064426Freely accessible. PMID 17606868. 
  10. ^ a b Yamamoto, T; Shimoyama, T; Kuriyama, M (8 December 2016). "Dietary and enteral interventions for Crohn's disease.". Current opinion in biotechnology. 44: 69–73. doi:10.1016/j.copbio.2016.11.011. PMID 27940405. 
  11. ^ Newsholme, P.; Lima, M. M. R.; Procopio, J.; Pithon-Curi, T. C.; Doi, S. Q.; Bazotte, R. B.; Curi, R. (2003). "Glutamine and glutamate as vital metabolites". Brazilian Journal of Medical and Biological Research. 36 (2): 153–163. doi:10.1590/S0100-879X2003000200002. PMID 12563517. 
  12. ^ Newsholme, P. (2001). "Why is L-glutamine metabolism important to cells of the immune system in health, postinjury, surgery or infection?". The Journal of Nutrition. 131 (9 Suppl): 2515S–2522S; discussion 2522S–4S. PMID 11533304. 
  13. ^ a b Watford, Malcolm (September 2015). "Glutamine and glutamate: Nonessential or essential amino acids?". Animal Nutrition. 1 (3): 119–122. doi:10.1016/j.aninu.2015.08.008. 
  14. ^ Stehle P, Kuhn KS (2015). "Glutamine: an obligatory parenteral nutrition substrate in critical care therapy". Biomed Res Int. 2015: 545467. doi:10.1155/2015/545467. PMC 4606408Freely accessible. PMID 26495301. 
  15. ^ Berretta, M; Michieli, M; Di Francia, R; Cappellani, A; Rupolo, M; Galvano, F; Fisichella, R; Berretta, S; Tirelli, U (1 January 2013). "Nutrition in oncologic patients during antiblastic treatment.". Frontiers in bioscience (Landmark edition). 18: 120–32. PMID 23276913. 
  16. ^ Tao, KM; Li, XQ; Yang, LQ; Yu, WF; Lu, ZJ; Sun, YM; Wu, FX (9 September 2014). "Glutamine supplementation for critically ill adults.". The Cochrane database of systematic reviews (9): CD010050. doi:10.1002/14651858.CD010050.pub2. PMID 25199493. 
  17. ^ Marini, JC (January 2016). "Interrelationships between glutamine and citrulline metabolism.". Current opinion in clinical nutrition and metabolic care. 19 (1): 62–6. PMC 4712452Freely accessible. PMID 26560519. 
  18. ^ Moe-Byrne, T; Brown, JV; McGuire, W (18 April 2016). "Glutamine supplementation to prevent morbidity and mortality in preterm infants.". The Cochrane database of systematic reviews. 4: CD001457. doi:10.1002/14651858.CD001457.pub6. PMID 27089158. 
  19. ^ "GlutaSolve, NutreStore, SYMPT-X G.I., SYMPT-X Glutamine (glutamine) Drug Side Effects, Interactions, and Medication Information on eMedicineHealth.". eMedicineHealth. Retrieved 24 January 2017. 

External links[edit]