återkopplingshämning

återkopplingshämning, also known as feedback inhibition, is a regulatory mechanism in biological systems. It occurs when the end product of a metabolic pathway inhibits an enzyme earlier in that same pathway. This prevents the overproduction of the end product and conserves cellular resources.

In many biochemical processes, a series of enzymatic reactions convert a starting molecule into a final product. Each step is catalyzed by a specific enzyme. In feedback inhibition, the final product of this sequence binds to an allosteric site on an enzyme that catalyzes one of the initial or rate-limiting steps. This binding causes a conformational change in the enzyme, reducing its activity or rendering it inactive.

This type of regulation is crucial for maintaining homeostasis. For example, in the synthesis of amino acids, if the concentration of a particular amino acid becomes too high, it will inhibit the enzymes responsible for its own production. Once the concentration of the amino acid decreases, the inhibition is released, and the pathway resumes its activity. This ensures that the cell produces just enough of the required molecule without wasting energy or accumulating toxic levels of intermediates. Feedback inhibition is a common and efficient way for cells to control metabolic flux.