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In biochemistry, allosteric regulation (or allosteric control) is the regulation of a protein by binding an effector molecule at a site other than the protein's active site. The site to which the effector binds is termed the ''allosteric site''. Allosteric sites allow effectors to bind to the protein, often resulting in a conformational change involving protein dynamics. Effectors that enhance the protein's activity are referred to as ''allosteric activators'', whereas those that decrease the protein's activity are called ''allosteric inhibitors''. Allosteric regulations are a natural example of control loops, such as feedback from downstream products or feedforward from upstream substrates. Long-range allostery is especially important in cell signaling. Allosteric regulation is also particularly important in the cell's ability to adjust enzyme activity. The term ''allostery'' comes from the Greek ''allos'' (ἄλλος), "other," and ''stereos'' (στερεὀς), "solid (object)." This is in reference to the fact that the regulatory site of an allosteric protein is physically distinct from its active site. == Models of allosteric regulation == Most allosteric effects can be explained by the ''concerted'' MWC model put forth by Monod, Wyman, and Changeux,〔J. Monod, J. Wyman, J.P. Changeux. (1965). On the nature of allosteric transitions:A plausible model. ''J. Mol. Biol.'', May;12:88-118.〕 or by the sequential model described by Koshland, Nemethy, and Filmer.〔D.E. Jr Koshland, G. Némethy, D. Filmer (1966) Comparison of experimental binding data and theoretical models in proteins containing subunits. ''Biochemistry''. Jan;5(1):365-8〕 Both postulate that enzyme subunits exist in one of two conformations, tensed (T) or relaxed (R), and that relaxed subunits bind substrate more readily than those in the tense state. The two models differ most in their assumptions about subunit interaction and the preexistence of both states. 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「Allosteric regulation」の詳細全文を読む スポンサード リンク
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