Biotechnology - Yu.O. Sazykin 2006

General Biotechnology
Molecular mechanisms of intracellular regulation and their application in biotechnological production
Catabolite repression in the development and production of drugs

Rapidly assimilated sources of carbon and energy (primarily glucose) trigger significant and rapid biomass accumulation in microorganisms. However, The Biosynthesis of many target products in biotechnological production, such as secondary metabolites and A number of Enzymes, drops sharply As a result. This phenomenon, initially referred to as the "glucose effect," was subsequently named catabolite repression.

In connection with this phenomenon, METABOLISM/2.html">THE CONCEPT OF transient repression was introduced. It describes a temporary yet sharp suppression of the synthesis of a corresponding catabolic enzyme when glucose is added to a microbial culture growing on a carbon and energy source that is assimilated more slowly than glucose. Later, as glucose remains present in the medium, the enzyme resumes synthesis, albeit at a low rate.

Another concept associated with catabolite repression is inducer exclusion. Glucose prevents The entry of the inducer (a less efficiently utilized substrate) into The Cell. Yet another concept is catabolite inhibition, which refers to the suppression of The activity of certain enzymes by the products of rapid Glucose Catabolism.

It has been established that catabolite repression occurs as a result of a rapid decrease in the intracellular content of cyclic 3,5-adenosine monophosphate (cAMP) triggered by The addition of glucose to the medium. Conversely, when glucose is removed from the medium, the intracellular cAMP level increases. Since The formation of cAMP from ATP is catalyzed by the enzyme adenylate cyclase, altering the activity of this enzyme requires obtaining Mutations in the Gene encoding it.

Catabolite repression is an unfavorable phenomenon that biotechnologists working in the antibiotic industry and in the microbial synthesis of medical-grade enzymes and certain recombinant Proteins must contend with. Despite a wealth of accumulated data, the relationship between catabolite repression and many metabolic processes—specifically, carbohydrate transport into the cell and excretion from it—is not yet fully understood. Therefore, In addition to selecting media with limited glucose content, significant attention is paid to working with producer strains, utilizing mutagenesis, Selection, and Introduction/32.html">Genetic Engineering Methods to obtain mutants that are insensitive to catabolite repression.