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al·lo·ster·ism, allostery (ă-los'ter-izm, -los'ter-ē),
allosteryA phenomenon in which a ligand binds to a specific receptor site on a protein, changing its shape, and altering the affinity for a ligand at a second site (e.g., either a receptor or a binding site); the ability of an effector molecule (ligand) to change the conformation and activity of a protein.
In allostery, the catalytic function of an enzyme may be modified by interaction with small molecules, not only at the active site but also at a spatially distinct (allosteric) site of different specificity. Allostery refers to an interaction of two or more functional sites on a protein, or two or more proteins, resulting in altered affinity of ligand binding; it depends on dynamic interaction with a substrate or other molecule—e.g., heme-heme interaction.
al·lo·ster·ism, allostery (al'ō-ster'izm, al'ō-ster'ē)
The influencing of an enzyme activity, or the binding of a ligand to a protein, by a change in the conformation of the protein, brought about by the binding of a substrate or other effector at a site (allosteric site) other than the active site of the protein.