A molecule, usually a product of a specific metabolic pathway, that combines with and activates a repressor produced by a regulator gene. The activated repressor then attaches to an operator gene site and inhibits activity of the structural genes. This homeostatic mechanism negatively regulates enzyme production in repressible enzyme systems.
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co·re·pres·sor .kō-ri-'pres-ər n a small molecule that activates a particular genetic repressor by combining with it
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co·re·pres·sor (ko″re-presґər) a small molecule that combines with a protein aporepressor molecule to form an active substance, which then binds to an operator gene and inhibits the synthesis of an enzyme. The mechanism is a negative control in inducible enzyme systems.Medical dictionary. 2011.