Answer – Allosteric inhibition is the process by which an inhibitor acts by attaching to an enzyme molecule at an allosteric site and inducing a physical change in its active site(s). 

Explanation:

Enzymes are protein molecules that act as catalysts for metabolic reactions that take place in the body. Each cell has its own enzymes based on its needs. 

However, the activity of these enzymes needs to be regulated in order to ensure efficient metabolism, and to avoid an excess of it. One of the means of maintaining this balance is the presence of regulatory molecules. On the basis of their function, these are of two kinds – activators and inhibitors. The former enhance the enzyme’s functioning, while the latter hinder it.

Inhibitors can perform their function via two main methods – competitive and non-competitive inhibition. Enzymes work such that the reactants, called substrates, have to bind with them at specific sites, called active sites, in order for the catalysis to occur. In competitive inhibition, the inhibitor binds with the enzyme at its active site, preventing the substrate from approaching the enzyme. Thus, the catalytic reaction/metabolism does not take place.

In non-competitive inhibition on the other hand, the inhibitor does not bind with the enzyme at the active site. Instead it binds at a different area, from which it interferes with the enzyme’s functioning. The substrate is allowed to attach itself to the enzyme, but the reaction will not take place.

Allosteric inhibition is a type of non-competitive inhibition. Allosteric inhibitors bind with the enzyme from areas that are not the active site. However, the change it evokes is different from that of non-competitive inhibition. When allosteric inhibitors attach with enzymes, they provoke a physical change in the structure of the active site, thus preventing the substrate from binding with it. 

This kind of inhibition can take place only in specific enzymes called allosteric enzymes. They often have multiple active sites, all of which are changed by the allosteric inhibitor.

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