catabolite repressionmedical dictionary

<biochemistry, molecular biology> Inducible enzyme systems in some microorganisms (such as the lac operon) that are repressed when a more favoured carbon source, such as glucose, is available.

Repression in E. coli is partially relieved if cAMP is bound to the cAMP catabolite activator protein (cAMP receptor protein, CRP) that binds to DNA upstream of the repressed operon concerned.

Catabolite repression (of the respiratory system) is seen in yeast in high glucose concentrations, though the mechanism is different.

(16 Mar 1998)