allosteric site

site (sīt) a place, position, or locus.

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allosteric site  a site on a multi-subunit enzyme that is not the substrate binding site but that when reversibly bound by an effector induces a conformational change in the enzyme, altering its catalytic properties.

antigen-binding site , antigen-combining site the region of the antibody molecule that binds to antigens.

binding site  in an enzyme or other protein, the three-dimensional configuration of specific groups on specific amino acids that binds specific compounds, such as substrates or effectors, with high affinity and specificity.

operator site  a site adjacent to the structural genes in the operon, where repressor molecules are bound, thereby inhibiting the transcription of the genes in the adjacent operon.

restriction site  a base sequence in a DNA segment recognized by a particular restriction endonuclease.

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allosteric site

n.

The place on an enzyme where a molecule that is not a substrate may bind, thus changing the shape of the enzyme and influencing its ability to be active.

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allosteric

pertaining to an effect on the biological function of a protein, produced by a compound not directly involved in that function (an allosteric effector) or to regulation of an enzyme involving cooperativity between multiple binding sites (allosteric sites).

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allosteric enzymes

any enzymes containing an allosteric site, where effector molecules can bind to increase or decrease the rate of reaction, in addition to an active site for substrate binding. Allosteric enzymes exhibit sigmoidal rather than Michaelis-Menten kinetics.

allosteric site

that site on an enzyme molecule which binds with a nonsubstrate molecule, inducing a conformational change that results in an alteration of the affinity of the enzyme for its substrate.