GLUTAMINE

'Glutamine' (Gln, Q) is one of the 20 amino acids encoded by the standard genetic code. Its side chain is an amide; it is formed by replacing a side-chain hydroxyl of glutamic acid with an amine functional group.

Contents

Biochemistry

Formation and nomenclature

Nutrition

Occurrences in nature

Functions

Use

Aiding gastrointestinal function

Aiding recovery after surgery

See also

References

External links

Biochemistry

Formation and nomenclature

Glutamine is genetically coded for by the DNA codons CAA and CAG. Glutamine's three-letter abbreviation is 'Gln', and its one-letter abbreviation is 'Q'. A three-letter designation for either glutamine or glutamic acid is 'Glx' (one-letter abbreviation: 'Z').
Like other amino acids, glutamine is biochemically important as a constituent of proteins. Glutamine is also crucial in nitrogen metabolism. Ammonia (formed by nitrogen fixation) is assimilated into organic compounds by converting glutamic acid to glutamine. The enzyme that accomplishes this is called glutamine synthetase. Glutamine can, hence, be used as a nitrogen donor in the biosynthesis of many compounds, including other amino acids, purines, and pyrimidines.
Artificial glutamine synthesis was first reported in 1933 in the 'Bergmann-Zervas carbobenzoxy method' ^[1]

Nutrition

Occurrences in nature

Glutamine is the most abundant naturally occuring, non-essential amino acid in the human body. 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. Food sources of glutamine include meat, poultry, fish, beans, eggs, and dairy products.

Functions

1) A substrate for DNA synthesis.

2) Major role in protein synthesis.

3) Promotes muscle growth and decreases muscle catabolism.

4) Primary source of fuel for enterocytes (cells lining the inside of the small intestine).

5) Precursor for rapidly dividing immune cells, thus aiding in immune function.

6) Regulation of acid-base balance in the kidney.

7) Alternative source of fuel for the brain and helps to block cortisol-induced protein catabolism.

Use

In catabolic states of injury and illness, GLN becomes conditionally-essential (requring intake from food or supplements). Glutamine has been studied extensively over the past 10-15 years and has been shown to be useful in treatment of serious illnesses, injury, trauma, burns, cancer and its treatment related side-effects as well as in wound healing for postoperative patients ^{(citation pending)}. That is why it is now also classified as a "nutraceutical". Glutamine is also marketed as a supplement used for muscle growth in weightlifting, bodybuilding, endurance and other sports.

Aiding gastrointestinal function

There have been several recent studies into the effects of glutamine and what properties it possesses, and, there is now a significant body of evidence that links glutamine-enriched diets with intestinal effects; aiding maintenance of gut barrier function, intestinal cell proliferation and differentiation, as well as generally reducing septic morbidity and the symptoms of Irritable Bowel Syndrome. The reason for such "cleansing" properties is thought to stem from the fact that the intestinal extraction rate of glutamine is higher
than that for other amino acids, and is therefore thought to be the most viable option when attempting to alleviate conditions relating to the gastrointestinal tract.
These conditions were discovered after comparing plasma concentration within the gut between glutamine-enriched and non glutamine-enriched diets. However, even though glutamine is thought to have "cleansing" properties and effects, it is unknown to what extent glutamine has clinical benefits, due to the varied concentrations of glutamine in varieties of food.

Aiding recovery after surgery

It is also known that glutamine has various effects in reducing healing time after operations. Hospital waiting times after abdominal surgery are reduced by providing parenteral nutrition regimens containing amounts of glutamine to patients. Clinical trials have revealed that patients on supplementation regimens containing glutamine have improved nitrogen balances, generation of cysteinyl-leukotrienes from polymorphonuclear neutrophil granulocytes and improved lymphocyte recovery and intestinal permeability (in postoperative patients) - in comparison to those who had no glutamine within their dietary regime; all without any side-effects.

See also

★ Bodybuilding supplements

★ Dietitian

References

1. Bergmann, M., Zervas, L., and Salzmann, L., Ber. them. Ges., 99, 1233 (1933).

# Boza J.J., Dangin M., Moennoz D., Montigon F., Vuichoud J., Jarret A., Pouteau E., Gremaud G., Oguey-Araymon S., Courtois D., Woupeyi A., Finot P.A. and Ballevre O. Free and protein-bound glutamine have identical splanchnic extraction in healthy human volunteers. ''Am J Physiol Gastrointest Liver Physiol. 2001 Jul; 281(1): G267-74. PMID 11408280'' Free text
# McAnena O.J., Moore F.A., Moore E.E., Jones T.N. and Parsons P. Selective uptake of glutamine in the gastrointestinal tract: confirmation in a human study. ''Br J Surg. 1991 Apr; 78(4): 480-2. PMID 1903318''
# Morlion B.J., Stehle P., Wachtler P., Siedhoff H.P., Koller M., Konig W., Furst P., Puchstein C. Total parenteral nutrition with glutamine dipeptide after major abdominal surgery. ''Ann Surg. 1998 Feb; 227(2): 302-8. PMID 9488531''
# Jiang Z.M., Cao J.D., Zhu X.G., Zhao W.X., Yu J.C., Ma E.L., Wang X.R., Zhu M.W., Shu H., Liu Y.W. The impact of alanyl-glutamine on clinical safety, nitrogen balance, intestinal permeability, and clinical outcome in postoperative patients: a randomised, double-blind, controlled study of 120 patients. ''JPEN J Parenter Enteral Nutr. 1999 Sep-Oct;23(5 Suppl):S62-6. PMID 10483898''

External links

★ Computational Chemistry Wiki

★ Nutrients and HIV: Part Three

★ Supplemental uses