Dictionary:

lysine

  (lī'sēn', -sĭn)

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An essential amino acid, C₆H₁₄N₂O₂, obtained by the hydrolysis of proteins and required by the body for optimum growth.

An essential amino acid of special nutritional importance, since it is the limiting amino acid in many cereals. Can be synthesized on a commercial scale, and when added to bread, rice, or cereal-based animal feeds, it improves the nutritional value of the protein.

Not all of the lysine in proteins is biologically available, since some is linked through its side-chain amino group, either to sugars (see Maillard reaction), or to other amino acids. These linkages are not hydrolysed by digestive enzymes, and so the lysine cannot be absorbed. Available lysine is that proportion of the protein-bound lysine in which the side-chain amino group is free, so that it can be absorbed after digestion of the protein.

An essential amino acid found in all proteins. Its concentration is relatively low in certain vegetables, such as cereal crops, so lysine is likely to be deficient in poorly designed vegetarian diets, but mixed vegetable diets are as good as meat. Low levels of lysine can slow down protein synthesis, resulting in poor muscle growth and repair.

One of the essential amino acids found in many proteins. An essential amino acid needed for proper growth in infants and for maintenance of nitrogen balance in adults. See also amino acids.

Description

Lysine is an amino acid not produced by the body, but essential to the growth of protein molecules in the body. It is necessary for tissue repair and growth, and for producing antibodies, enzymes, and hormones. Lysine is found in other protein sources, such as red meats, chicken, and turkey. Most individuals have an adequate intake of lysine; however lysine levels may be low in vegetarians and low-fat dieters. Without enough lysine or any other of the eight essential amino acids, the body cannot build protein to sustain muscle tissue.

General Use

The body only uses L-lysine to build protein. Since amino acid molecules are asymmetrical, each amino acid exists as both a right- and left-handed form, distinguished as "D" and "L" respectively. As a supplement, L-lysine is used to treat the herpes simplex virus, help prevent osteoporosis and cataracts, and boost the immune system.

Herpes Simplex Virus Remedy

In the 1950s, scientists discovered that foods containing certain amino acids could encourage or discourage the growth of the herpes virus. When added to the herpes virus, the amino acid arginine increases the growth of the virus. Lysine, on the other hand, suppresses it. Since the virus can cause cold sores, canker sores, and genital sores, L-lysine supplements increase the ratio of lysine to arginine in the body, curing the outbreak of the virus. Avoiding foods with arginine and eating foods with a higher lysine content will also help alleviate the symptoms of the virus.

Foods containing arginine:

• gelatin
• nuts
• chocolate

Foods containing lysine:

• milk
• soybeans
• meat
• lentils
• spinach

Other Uses

Lysine also promotes the body's absorption of calcium, helping to prevent osteoporosis. It slows the damage to the eye caused by diabetes, and it may help cure atherosclerosis. Since it is used to slow the herpes simplex virus, its antiviral properties may help treat chronic fatigue syndrome, hepatitis, and HIV.

Preparations

L-lysine is best taken as a single supplement and not in combination with other amino acids. Such combinations are touted as nutritional supplements that build more muscle and are often used by athletes and bodybuilders. However, too much protein strains the functions of the liver and kidneys and can cause other health problems. The single supplement should be taken on an empty stomach because larger amounts of the amino acid can build up in the blood and brain, enhancing its health benefits. Supplements are best used by individuals suffering from a herpes outbreak or by vegetarians and low-fat dieters. Postmenopausal women can take lysine to encourage absorption of calcium by the body.

Precautions

Supplemental combinations of amino acids are not recommended to build muscle. Excessive build-up of protein in the body can cause kidney and liver problems.

Some consumers are sensitive or allergic to soybeans, a popular food used by vegetarians to replace the natural supply of lysine found in many meats. However in 2002, researchers announced progress in creating soybeans that could be tolerated by consumers with those sensitivities by shutting off a gene in soybean seeds believed responsible for causing the allergies.

Side Effects

None reported.

Interactions

None reported.

Resources

Books

Atkins, Robert C. M.D. Dr. Atkins'Vita-Nutrient Solution. New York: Simon & Schuster, 1998.

Carper, Jean. Food—Your Miracle Medicine: How Food Can Prevent and Cure Over 100 Symptoms and Problems. New York: HarperCollins, 1993.

Duke, James A. The Green Pharmacy. Emmaus, PA: Rodale Press, 1997.

Periodicals

Gramling, Jack. "Lysine Helped CFIDS Sufferer Gain Control of his Life." Medical Update (October 1995): 1-2.

Krieter, Ted. "A Microbiologist Who Stopped Her Fever Blisters." Saturday Evening Post (November-December 1995): 54-56.

"Lysine and Cold Sores." Medical Update (January 1995): 1.

"New Soybeans Could Help Consumers with Soy Allergen." On the Plate (August 31, 2002).

Stauth, Cameron. "Beating Chronic Fatigue." Saturday Evening Post (November-December 1995): 50-54.

Other

"Lysine." Medicaldictionary.net. http://www.medicaldictionary.net/lysine.htm (July 24, 2000).

[Article by: Jacqueline L. Longe; Teresa G. Odle]

For more information on lysine, visit Britannica.com.

An essential amino acid found in all animal proteins, but which is low in some plant proteins (e.g. cereals).

Lys; a naturally occurring, essential amino acid, important in the formation of collagen, fibrin and keratin. Often the first limiting essential amino acid in growth and production. Nutritional deficiency in Bronzewing turkeys causes deficient pigmentation in the feathers.

• l. vasopressin — see vasopressin.

Lysine
Systematic (IUPAC) name
2,6-diaminohexanoic acid
Identifiers
CAS number	56-87-1
PubChem	866
Chemical data
Formula	C6H14N2O2
Molar mass	146.188 g/mol
SMILES	C(CCN)CC(C(=O)O)N
Complete data

Lysine (abbreviated as Lys or K)^[1] is an α-amino acid with the chemical formula HO₂CCH(NH₂)(CH₂)₄NH₂. This amino acid is an essential amino acid, which means that humans cannot synthesize it. Its codons are AAA and AAG.

Lysine is a base, as are arginine and histidine. The ε-amino group often participates in hydrogen bonding and as a general base in catalysis. Common posttranslational modifications include methylation of the ε-amino group, giving methyl-, dimethyl-, and trimethyllysine. The latter occurs in calmodulin. Other posttranslational modifications include acetylation. Collagen contains hydroxylysine which is derived from lysine by lysyl hydroxylase. O-Glycosylation of lysine residues in the endoplasmic reticulum or Golgi apparatus is used to mark certain proteins for secretion from the cell.

Biosynthesis

As an essential amino acid, lysine is not synthesized in animals, hence it must be ingested as lysine or lysine-containing proteins. In plants and microorganisms, it is synthesized from aspartic acid, which is first converted to β-aspartyl-semialdehyde. Cyclization gives dihydropicolinate, which is reduced to Δ¹-piperidine-2,6-dicarboxylate. Ring-opening of this heterocycle gives a series of derivatives of pimelic acid, ultimately affording lysine. Enzymes involved in this biosynthesis include:^[2]

1. Aspartokinase
2. β-aspartate semialdehyde dehydrogenase
3. Dihydropicolinate synthase
4. Δ¹-piperdine-2,6-dicarboxylate dehydrogenase
5. N-succinyl-2-amino-6ketopimelate synthase
6. Succinyl diaminopimelate aminotransferase
7. Succinyl diaminopimelate desuccinylase
8. Diaminopimelate epimerase
9. Diaminopimelate decarboxylase

Metabolism

Lysine is metabolised in mammals to give acetyl-CoA, via an initial transamination with α-ketoglutarate. The bacterial degradation of lysine yields cadaverine by decarboxylation.

Synthesis

Synthetic, racemic lysine has long been known.^[3] A practical synthesis starts from caprolactam.^[4]

Dietary sources

The human nutritional requirement is 1–1.5 g daily. It is the limiting amino acid in all cereal grains, but is plentiful in all pulses (legumes). Plants that contain significant amounts of lysine include:^{[citation needed]}

• Buffalo Gourd (10,130–33,000 ppm) in seed
• Berro, Watercress (1,340–26,800 ppm) in herb.
• Soybean (24,290–26,560 ppm) in seed.
• Carob, Locust Bean, St.John's-Bread (26,320 ppm) in seed;
• Common Bean (Black Bean, Dwarf Bean, Field Bean, Flageolet Bean, French Bean, Garden Bean, Green Bean, Haricot, Haricot Bean, Haricot Vert, Kidney Bean, Navy Bean, Pop Bean, Popping Bean, Snap Bean, String Bean, Wax Bean) (2,390–25,700 ppm) in sprout seedling;
• Ben Nut, Benzolive Tree, Jacinto (Sp.), Moringa (aka Drumstick Tree, Horseradish Tree, Ben Oil Tree), West Indian Ben (5,370–25,165 ppm) in shoot.
• Lentil (7,120–23,735 ppm) in sprout seedling.
• Asparagus Pea, Winged Bean (aka Goa Bean) (21,360–23,304 ppm) in seed.
• Fat Hen (3,540–22,550 ppm) in seed.
• Lentil (19,570–22,035 ppm) in seed.
• White Lupin (19,330–21,585 ppm) in seed.
• Black Caraway, Black Cumin, Fennel-Flower, Nutmeg-Flower, Roman Coriander (16,200–20,700 ppm) in seed.
• Spinach (1,740–20,664 ppm).
• Amaranth, Quinoa

Good sources of lysine are foods rich in protein including meat (specifically red meat, pork, and poultry), cheese (particularly parmesan), certain fish (such as cod and sardines), nuts and eggs.

Properties

L-Lysine is a necessary building block for all protein in the body. L-Lysine plays a major role in calcium absorption; building muscle protein; recovering from surgery or sports injuries; and the body's production of hormones, enzymes, and antibodies.

Clinical significance

It has been suggested that lysine may be beneficial for those with herpes simplex infections.^[5] However, more research is needed to fully substantiate this claim. For more information, refer to Herpes simplex - Lysine.

Lysine can help to alleviate the symptoms of coldsores. They help to speed up the healing process if taken immediately.

Trivia

-In the movie Jurassic Park the dinosaurs were genetically altered so they could not produce lysine. This was supposed to prevent the dinosaurs from leaving the park.

References

1. ^ IUPAC-IUBMB Joint Commission on Biochemical Nomenclature. Nomenclature and Symbolism for Amino Acids and Peptides. Recommendations on Organic & Biochemical Nomenclature, Symbols & Terminology etc. Retrieved on 2007-05-17.
2. ^ Nelson, D. L.; Cox, M. M. "Lehninger, Principles of Biochemistry" 3rd Ed. Worth Publishing: New York, 2000. ISBN 1-57259-153-6.
3. ^ Braun, J. V. “Synthese des inaktiven Lysins aus Piperidin" Berichte der deutschen chemischen Gesellschaft 1909, Volume 42, p 839-846. DOI: 10.1002/cber.190904201134.
4. ^ Eck, J. C.; Marvel, C. S. “dl-Lysine Hydrochlorides” Organic Syntheses, Collected Volume 2, p.374 (1943). http://www.orgsyn.org/orgsyn/pdfs/CV2P0374.pdf
5. ^ Griffith RS, Norins AL, Kagan C. (1978). "A multicentered study of lysine therapy in Herpes simplex infection". Dermatologica. 156 (5): 257-267. PMID 640102. 

See also

• Acetyllysine
• Lysine price-fixing conspiracy
• Deamination
• Saccharopine

Sources

• Much of the information in this article has been translated from German Wikipedia.
• Lide, D. R. (Ed.) (2002). CRC Handbook of Chemistry and Physics (83rd Edn.). Boca Raton (FL):CRC Press. ISBN 0-8493-0483-0. 

External links

• Lysine biosynthesis (early stages), Lysine biosynthesis (later stages), and Lysine catabolism at Queen Mary, University of London
• Computational Chemistry Wiki at compchemwiki.org
• L-Lysine at PDRhealth.com

Major families of biochemicals
Peptides | Amino acids | Nucleic acids | Carbohydrates | Lipids | Terpenes | Carotenoids | Tetrapyrroles | Enzyme cofactors | Steroids | Flavonoids | Alkaloids | Polyketides | Glycosides
Analogues of nucleic acids:	The 20 Common Amino Acids	Analogues of nucleic acids:
Alanine (dp) | Arginine (dp) | Asparagine (dp) | Aspartic acid (dp) | Cysteine (dp) | Glutamic acid (dp) | Glutamine (dp) | Glycine (dp) | Histidine (dp) | Isoleucine (dp) | Leucine (dp) | Lysine (dp) | Methionine (dp) | Phenylalanine (dp) | Proline (dp) | Serine (dp) | Threonine (dp) | Tryptophan (dp) | Tyrosine (dp) | Valine (dp)

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