Low Glutamine Concentrations Induce Phenotypical and Functional ...
Glutamine kháng U937
From Wikipedia, the free encyclopedia
L-Glutamine
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| Names | |
|---|---|
| IUPAC name
Glutamine
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| Other names
L-Glutamine
(levo)glutamide 2-Amino-4-carbamoylbutanoic acid | |
| Identifiers | |
3D model (JSmol)
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| Abbreviations | Gln, Q |
| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.000.266 |
| EC Number | 200-292-1 |
| KEGG | |
PubChem CID
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| UNII | |
| 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) |
Chiral rotation([α]D)
| +6.5º (H2O, c = 2) |
| Pharmacology | |
| A16AA03 (WHO) | |
| Supplementary data page | |
| Refractive index (n), Dielectric constant (εr), 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).
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 verify (what is   ?) | |
| 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 amidewhich 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]
Contents
[hide]Functions[edit]
Glutamine plays a role in a variety of biochemical functions:
- Protein synthesis, as any other of the 20 proteinogenic amino acids
- Lipid synthesis, especially by cancer cells.[5][6]
- Regulation of acid-base balance in the kidney by producing ammonium[7]
- Cellular energy, as a source, next to glucose[8]
- Nitrogen donation for many anabolic processes, including the synthesis of purines[4]
- Carbon donation, as a source, refilling the citric acid cycle[9]
- Nontoxic transporter of ammonia in the blood circulation
- Precursor to the neurotransmitter glutamate
On the level of tissue, glutamine plays a role in maintaining the normal integrity of the intestinal mucosa.[10]
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 lungs and 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]
Nutrition[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] Humans obtain glutamine through catabolism of proteins in foods they eat.[13] In states where tissue is being built or repaired, like growth of infants, or healing from traumatic wounds or severe illness, glutamine becomes conditionally essential.[13]
Medical food[edit]
Glutamine is 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.[14]
Research[edit]
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.[16]
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.[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]
Safety[edit]
Glutamine is safe in adults and in preterm infants.[19] 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.[19] The observed safe level for L-glutamine in normal healthy adults is 14 g/day.[20]
Adverse effects of glutamine have been described for people receiving home parenteral nutrition and those with liver-function abnormalities.[21] 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.[22]
Glutamine withdrawal in subjects adapted to enhanced consumption may raise the risk of health problems such as infections or impaired integrity of the intestine.[22]
