- active r. a r. that combines directly with an operator gene to repress the operator and its structural genes, thus repressing protein synthesis; an active r. may be repressed by an inducer, with resulting protein synthesis; a homeostatic mechanism for regulation of inducible enzyme systems.
- inactive r. a r. that cannot combine with an operator gene until it has combined with a corepressor (usually a product of a protein pathway); after activation, the r. arrests production of the proteins controlled by the operator gene; a homeostatic mechanism for regulation of repressible enzyme systems.
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re·pres·sor ri-'pres-ər n one that represses esp a protein that is determined by a regulatory gene, binds to a genetic operator, and inhibits the initiation of transcription of messenger RNA
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re·pres·sor (re-presґər) [L. “a restrainerâ€] in genetics, a protein produced by a regulator gene that binds to the operator region of a structural gene to block initiation of transcription of the gene or operon.Medical dictionary. 2011.