Difference Between Allosteric and Non-competitive Inhibition

Definition

Allosteric inhibition refers to the slowing down of enzyme-catalyzed chemical reactions that occur in cells while non-competitive inhibition refers to a type of enzyme inhibition where the inhibitor reduces the activity of the enzyme and binds equally well to the enzyme.

Significance

Allosteric inhibition is a type of enzyme inhibition allowing the binding of small molecules to the enzyme non-other than the active site of the enzyme in order to change the activity of the enzyme while non-competitive inhibition allows the binding of inhibitor molecules reducing the activity of the enzyme.  

Correlation

The types of allosteric inhibition include competitive, non-competitive, or uncompetitive inhibition while non-competitive inhibition is a type of allosteric inhibition.

Importance

Allosteric inhibition is a physiological process while non-competitive inhibition is a non-physiological process.

Competition with the Substrate

Allosteric inhibition competes with the substrate while non-competitive inhibition does not compete with the substrate.

Action

Allosteric inhibition allows the binding of small molecules into the allosteric site or regulatory site while non-competitive inhibition allows the binding of small molecules to non-substrate sites.

Conformational Change

Allosteric inhibition changes the conformation of the enzyme while non-competitive inhibition does not change the conformation of the enzyme.

Extent of Inhibition

Allosteric inhibition allows the binding of more inhibitor molecules to increase the degree of inhibition while non-competitive inhibition does not have a different degree of inhibition.

Effect on Enzyme

Allosteric inhibition adjusts the activity of the enzyme while non-competitive inhibition keeps the enzyme non-functional.

In brief, allosteric and non-competitive inhibition are two types of inhibitory processes of enzymes. Generally, allosteric inhibition is a physiological process allowing the binding of small molecules to sites non-other than the active site of the enzyme. Therefore, small molecules bind to the allosteric or regulatory site of the enzyme. Also, the degree of inhibition depends on the number of inhibitor molecules that bind to the enzyme molecule. In addition to that, allosteric inhibition adjusts the activity of the enzyme. In comparison, non-competitive inhibition is a non-physiological process that allows the binding of small molecules to the non-substrate sites reducing the activity of the enzyme. Also, it makes the enzyme non-functional. Therefore, the main difference between allosteric and non-competitive inhibition is the type of inhibition of enzymes.