| Description | See ι-LYSINE MONOCHLORIDE. |
| Chemical Properties | L-Lysine is an essential amino acid (a protein building block) that cannot be produced by the body from other nutri ents. It helps ensure adequate absorption of calcium and the formation of collagen for bone, cartilage and connective tissue. Thiscompound is odorless. |
| Chemical Properties | White to pale yellow crystalline powder |
| Occurrence | Some natural food sources for l-lysine include lima beans, kidney beans, potatoes, corn, red meat, fish andmilk. |
| Uses | L-Lysine is an essential amino acid used in human nutrition. It plays a vital role in calcium absorption, building muscle protein and recovering from surgery or sports injuries. It is used for the treatment of herpes infections and cold sores. Its derivatives lysine acetylsalicylate is utilized to treat pain as well as to detoxify the body after heroin use. It is an important additive to animal feed. Further, it is used in many foods, especially red meats, fish and dairy products. |
| Uses | Essential amino acid for human development. Lysine residues are useful in many cellular processes, due to their ability to accept a wide variety of post-translational modifications. |
| Uses | lysine is a skin-conditioning amino acid. |
| Definition | ChEBI: An L-alpha-amino acid; the L-isomer of lysine. |
| Preparation | Produced by fermentation. Also produced by use of continuous ion exchange technology. |
| Biotechnological Production | C. glutamicum and, to a lesser extent, E. coli are the main organisms used todayfor industrial L-lysine production. The first L-producing strains based on C. glutamicumwere reported in 1961, and those based on E. coli in 1995. Theadvantages of using E. coli versus C. glutamicum include the achievement ofhigher growth rates at higher fermentation temperatures. The formation of lysineis highly influenced by two enzymes, aspartate kinase (AK) and homoserinedehydrogenase (HDH). AK converts aspartate into aspartate semialdehyde, and is highly feedback-inhibited by lysine and threonine. HDH converts aspartate semialdehydeinto homoserine, which is an intermediate for the biosynthesis of threonine,methionine, and isoleucine. L-Lysine–producing strains therefore oftencontain a deregulated AK and/or a reduced activity HDH. Despite theimprovement of the flux from aspartate towards lysine, the availability of keymetabolites from the central metabolic pathways is also essential. Here the formationof oxaloacetate directly from phosphoenol pyruvate or via pyruvate isessential for the carbon yield as some unnecessary cycles are included. Forexample, inactivation of the enzyme phosphoenol pyruvate carboxykinase, whichcatalyzes the reverse reaction from oxaloacetate to phosphoenol pyruvate gave animprovement in lysine formation. By overexpression of pyruvate carboxylase,the conversion yield of glucose to lysine could be increased by 50 %. With asynthetic lysine hyperproducing strain, containing 12 defined modifications fromthe wild type, a carbon yield of 0.55 g/g and a product titer of 120 g/L over 30 hfermentation could be obtained.
Today, however, the main commercial process for L-lysine remains the fermentationof C. glutamicum. This is performed in fed-batch mode in large-scalefermenters of up to 500 m3 volume, with production capacities in excess of100,000 tonnes. The commercial manufacturing process has been comprehensivelydescribed by Pfefferle. |
| Aroma threshold values | Detection: 500 ppm |
| Synthesis Reference(s) | Journal of the American Chemical Society, 71, p. 3161, 1949 DOI: 10.1021/ja01177a063 |
| General Description | L-Lysine is a basic amino acid. |
| reaction suitability | reaction type: solution phase peptide synthesis |
| Safety Profile | An experimental teratogen. Experimental reproductive effects. When heated to decomposition it emits toxic fumes of NOx. |
| Veterinary Drugs and Treatments | Lysine may be effective in suppressing FHV-1 infections in cats. |
| Purification Methods | Crystallise L-lysine from aqueous EtOH. [Greenstein & Winitz The Chemistry of the Amino Acids J. Wiley, Vol 3 pp 2097-2122 1961, Kearley & Ingersoll J Am Chem Soc 73 5783 1951, Beilstein 4 IV 2717.] |
