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|Section2= |Section6= |Section8= }} Monensin is a polyether antibiotic isolated from ''Streptomyces cinnamonensis''. It is widely used in ruminant animal feeds.〔Patrick Butaye, Luc A. Devriese, Freddy Haesebrouck "Antimicrobial Growth Promoters Used in Animal Feed: Effects of Less Well Known Antibiotics on Gram-Positive Bacteria" Clinical Microbiology Reviews, 2003, p. 175-188, Vol. 16. 〕〔 The structure of monensin was first described by Agtarap ''et al.'' in 1967, and was the first polyether antibiotic to have its structure elucidated in this way. The first total synthesis of monensin was reported in 1979 by Kishi ''et al.'' ==Mechanism of action== Monensin A is an ionophore related to the crown ethers with a preference to form complexes with monovalent cations such as: Li+, Na+, K+, Rb+, Ag+, and Ti+.〔A. Huczyński, M. Ratajczak-Sitarz, A. Katrusiak, B. Brzezinski, "Molecular structure of the 1:1 inclusion complex of Monensin A lithium salt with acetonitrile", ''J. Mol. Struct.'', 2007, 871, 92-97, 〕〔M. Pinkerton, L. K. Steinrauf, "Molecular structure of monovalent metal cation complexes of monensin", ''J. Mol. Biol.'', 1970 49(3), 533-546〕 Monensin A is able to transport these cations across lipid membranes of cells in an electroneutral (i.e. non-depolarizing) exchange, playing an important role as an Na+/H+ antiporter. Recent studies have shown that monensin may transport sodium ion through the membrane in both electrogenic and electroneutral manner. This approach explains ionophoric ability and in consequence antibacterial properties of not only parental monensin, but also its derivatives that do not possess carboxylic groups. It blocks intracellular protein transport, and exhibits antibiotic, antimalarial, and other biological activities.〔H. H. Mollenhauer, D. J. Morre, L. D. Rowe, "Alteration of intracellular traffic by monensin; mechanism, specificity and relationship to toxicity", ''Biochim. Biophys. Acta'', 1990, 1031(2), 225-246, 〕 The antibacterial properties of monensin and its derivatives are a result of their ability to transport metal cations through cellular and subcellular membranes.〔A. Huczyński, J. Stefańska, P. Przybylski, B. Brzezinski and F. Bartl, "Synthesis and antimicrobial properties of Monensin A esters", ''Bioorg. Med. Chem. Lett.'', 2008, 18, 2585-2589, 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Monensin」の詳細全文を読む スポンサード リンク
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