Lysine hydrochloride

70-54-2DLY56-87-1LY923-27-3DY Interactive imageZwitterion:Interactive imageProtonated zwitterion:Interactive image CHEBI:25094Y ChEMBL28328Y 843Y5747LY 724 C16440Y 866 AI4RT59273DLYK3Z4F929H6LY3HQ6U6424QDY DTXSID90859004 InChI=1S/C6H14N2O2/c7-4-2-1-3-5(8)6(9)10/h5H,1-4,7-8H2,(H,9,10)YKey: KDXKERNSBIXSRK-UHFFFAOYSA-NYInChI=1/C6H14N2O2/c7-4-2-1-3-5(8)6(9)10/h5H,1-4,7-8H2,(H,9,10)Key: KDXKERNSBIXSRK-UHFFFAOYAY C(CCN)C[C@@H](C(=O)O)NZwitterion: C(CC[NH3+])C[C@@H](C(=O)[O-])NProtonated zwitterion: C(CC[NH3+])C[C@@H](C(=O)[O-])[NH3+] Lysine(symbolLysorK)is anα-amino acidthat is aprecursorto manyproteins. Lysine contains an α-amino group (which is in theprotonated−NH+3form when the lysine is dissolved in water atphysiological pH), an α-carboxylic acid group (which is in the deprotonated−COO−form when the lysine is dissolved in water at physiological pH), and a side chain(CH2)4NH2(which is partially protonated when the lysine is dissolved in water at physiological pH), and so it is classified as abasic, charged (in water at physiological pH),aliphaticamino acid. It is encoded by thecodonsAAA and AAG. Like almost all other amino acids, the α-carbon ischiraland lysine may refer to eitherenantiomeror aracemic mixtureof both. For the purpose of this article, lysine will refer to the biologically active enantiomerL-lysine, where the α-carbon is in theSconfiguration. The human body cannot synthesize lysine. It isessential in humansand must therefore be obtained from the diet. In organisms that synthesize lysine, two mainbiosynthetic pathwaysexist, thediaminopimelateandα-aminoadipatepathways, which employ distinctenzymesandsubstratesand are found in diverse organisms. Lysinecatabolismoccurs through one of several pathways, the most common of which is thesaccharopine pathway. Lysine plays several roles in humans, most importantlyproteinogenesis, but also in the crosslinking ofcollagenpolypeptides, uptake of essential mineral nutrients, and in the production ofcarnitine, which is key infatty acid metabolism. Lysine is also often involved inhistone modifications, and thus, impacts theepigenome. The ε-amino group often participates in hydrogen bonding and as a general base incatalysis. The ε-ammoniumgroup (−NH+3) is attached to the fourth carbon from the α-carbon, which is attached to thecarboxyl(−COOH) group. Due to its importance in several biological processes, a lack of lysine can lead to several disease states including defective connective tissues, impaired fatty acid metabolism, anaemia, and systemic protein-energy deficiency. In contrast, an overabundance of lysine, caused by ineffective catabolism, can cause severeneurological disorders. Lysine was first isolated by the German biological chemist Ferdinand Heinrich Edmund Drechsel in 1889 from hydrolysis of the proteincasein,and thus named it Lysin, fromGreekλύσις(lysis)'loosening'.In 1902, the German chemistsEmil FischerandFritz Weigertdetermined lysine's chemical structure by synthesizing it. The one-letter symbol K was assigned to lysine for being alphabetically nearest, with L being assigned to the structurally simpler leucine, and M to methionine.