Basic amino acid. Positively charged at neutral pH. Hydrophilic.

Formula: C6H14N2O2
Molecular Weight: 146.19
Structure: (amino acid group)-CH2-CH2-CH2-CH2-NH2
Three-letter code: Lys
One-letter code: K

structural formula for lysine:

                           H
                            \
H    H   H     H   H     H   N -- H
 \    \ /       \ /       \ /
  N -- C -- C -- C -- C -- C -- O -- H
 /         / \       / \    \
H         H   H     H   H    C == O
One of nine essential amino acids required in the human diet. As with any amino acid, lysine is a building block for making human proteins. Lysine helps with calcium absorption, the formation of collagen, and bone growth.

Lysine is found in most protein food sources but there's a lot more of it in animal protein (fish, meat, dairy products) than other sources. Grains and cereal generally lack lysine (with the exception of wheat germ, buckwheat, amaranth, quinoa, and rice). Companies like Novartis are working to "improve" upon nature by developing genetically modified versions of corn that contains lysine.

Vegetarians can get their lysine from legumes, especially soy. Fruits and vegetables have some, but not nearly as much as animal protein. It turns up in high concentrations in spirulina, parsley, fenugreek seed.

It has been used orally in the prevention and treatment of herpes infections (genital herpes and cold sores) and canker sores; in the treatment of Bell's palsy; and to improve calcium use in the body. Linus Pauling thought that lysine (along with vitamin C) could dissolve atherosclerotic plaques in the body.

Anabolic biosynthesis of Lysine is unusual among amino acids in that there are two dissimilar pathways of production.

One is the diaminopimelic acid pathway (DAP), and the other is the α-aminoadipic acid route (AAA).

What is interesting is that they are completely dissimilar, using different enzymes and having evolved separately in different lineages of life.

The diaminopimelic acid pathway is most commonly found in Plants - Kingdom Plantae but can pretty much be considered universal.

The less common α-aminoadipic acid route (AAA). was once though to be unique to fungi1. But it has since been discovered in at least two other groups:

1Parts of the AAA pathway of lysine degradation are also found in animals, contributing to the theory that the Animal and Fungal kingdoms are much more more closely related than Plants and Fungi, as was once assumed.

ref: Journal of Molecular Evolution DOI: 10.1007/s00239-002-2340-2 © Springer-Verlag New York Inc. 2002 Molecular Evolution of the Lysine Biosynthetic Pathways A.M. Velasco, J.I. Leguina, and A. Lazcano

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