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( Lysine)
Lysine (abbreviated as Lys or K)[1] is an a-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 e-amino group often participates in hydrogen bonding and as a general base in catalysis. Common posttranslational modifications include methylation of the e-amino group, giving methyl-, dimethyl-, and trimethyllysine. The latter occurs in calmodulin. Other posttranslational modifications at lysine residues include acetylation and ubiquitination. 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. 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 ß-aspartyl-semialdehyde. Cyclization gives dihydropicolinate, which is reduced to ?1-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] Lysine is metabolised in mammals to give acetyl-CoA, via an initial transamination with a-ketoglutarate. The bacterial degradation of lysine yields cadaverine by decarboxylation.
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Know Your Bodybuilding Supplement - L-Lysine by Rick Mitchell
Lysine is an essential amino acid therefore it must be obtained from the diet as the body cannot produce its own. It is an essential building block for all protein in the body and can be found in animal meats, fish, dairy products, le...
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