Feedback inhibition refers to a situation where the resulting product in a reaction affects the enzyme that aided its production. This happens when the destructor binds to the next active holding site which varies from that which is attached to the first reactant. This causes the enzyme’s shape to change meaning it can no longer cause a reaction. This kind of inhibition is usually done to as a control mechanism to address metabolic requirements of the organism or cell. Most mechanisms like cellular respiration and synthesis of bile acid within the liver utilize feedback inhibition frequently.
How Feedback Inhibition Operates
Feedback inhibition operates through enzyme deactivation though the product generated as a result of the reaction catalyzed by the enzyme. Enzymes hold on to molecules that have dynamic sites specifically made to fit the molecule that goes through reaction. The enzymes usually have an extra dynamic site where the reaction product can hold to. This leads to a spatial rearrangement of the enzyme so that it cannot hold to the first reagent anymore causing the reaction to stop. In some cases, enzymes like pyruvate kinase that aid in breaking glucose down are modified chemically to stop reactions.
One objective of feedback inhibition is stopping production of too much product. It balances generation of amino acids, which are the blocks used to build proteins. For instance, a product generated by enzyme threonine deaminase called amino acid isoleucine inhibits it. Without inhibiting the reaction, the enzyme cannot product other amino acids required by the cell. However, in case isoleucine available is not sufficient, the reaction will restart again. To achieve this, the enzyme holds onto an amino acid called valine that switches the enzyme on again. A malfunction in the feedback inhibition can lead to increased risks of ailments such as heart disease.