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|Section2= |Section3= }} Enterobactin (also known as Enterochelin) is a high affinity siderophore that acquires iron for microbial systems. It is primarily found in Gram-negative bacteria, such as ''Escherichia coli'' and ''Salmonella typhimurium''. Enterobactin is the strongest siderophore known, binding to the ferric ion (Fe3+) with the affinity (K = 1052 M−1). This value is substantially larger than even some synthetic metal chelators, such as EDTA (Kf,Fe3+ ~ 1025 M−1). () Due to its high affinity, enterobactin is capable of chelating even in environments where the concentration of ferric ion is held very low, such as within living organisms. Enterobactin can extract iron even from the air. Pathogenic bacteria can steal iron from other living organisms using this mechanism, even though the concentration of iron is kept extremely low due to the toxicity of free iron. ==Structure and biosynthesis== Chorismic acid, an aromatic amino acid precursor, is converted to 2,3-dihydroxybenzoic acid (DHB) by a series of enzymes, EntA, EntB and EntC. An amide linkage of DHB to L-serine is then catalyzed by EntD, EntE, EntF and EntB. Three molecules of the DHB-Ser formed undergo intermolecular cyclization, yielding enterobactin. () Although a number of stereoisomers are possible due to the chirality of the serine residues, only the Δ-cis isomer is metabolically active. The first three-dimensional structure of a metal enterobactin complex was determined as the vanadium(IV) complex. 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「Enterobactin」の詳細全文を読む スポンサード リンク
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