In genetics and biochemistry, a repressor gene inhibits the activity of an operator gene. By inactivating the repressor, the operator gene becomes active again. This effect is called derepression.

Derepression of ALA synthase

One example is the effect of drugs on the activity of ALA synthase, an enzyme involved in heme-synthesis. When inducing for example phenobarbital, griseofulvin or hydantoins, the activity of ALA synthase will rise. The cause is a production of cytochrome P450-production, induced by the drugs, consuming heme. When the amount of heme in the liver decreases, it no longer act as a repressor for its synthesis. On the contrary, ALA synthase increases which leads to an increase in heme-production.


  • Pamela C., Ph.D. Champe, Richard A., Ph.D. Harvey, Denise R., Ph.D. Ferrier, (2004). Lippincott's Illustrated Reviews: Biochemistry 319 (3rd edition ed.). Hagerstown, MD: Lippincott Williams & Wilkins. ISBN 0-7817-2265-9. 

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  • derepression — derepression. См. дерепрессия. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • derepression — noun see derepress …   New Collegiate Dictionary

  • derepression — Anything that stops the repression of a gene thereby allowing expression to occur …   Dictionary of molecular biology

  • derepression — See derepress. * * * …   Universalium

  • derepression — noun The inactivation of a repressor gene …   Wiktionary

  • derepression — A homeostatic mechanism for regulating enzyme production in an inducible enzyme system : an inducer, usually a substrate of a specific enzyme pathway, by combining with an active repressor (produced by a re …   Medical dictionary

  • derepression — de·repression …   English syllables

  • derepression — The process of turning on the expression of a gene or set of genes whose expression has been repressed (turned off), usually by the displacement of a repressor from a promoter, since, when attached to the DNA, the repressor prevents transcription …   Glossary of Biotechnology

  • derepression — noun see derepress * * * derepressˈion noun • • • Main Entry: ↑derepress …   Useful english dictionary

  • дерепрессия — derepression дерепрессия. Индукция транскрипции гена в результате подавления функций репрессора (нарушения его связи с операторной зоной оперона <operon> под действием индуктора, мутаций и т.п.). (Источник: «Англо русский толковый словарь… …   Молекулярная биология и генетика. Толковый словарь.

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