What is the Difference Between Reversible and Irreversible Inhibition?

The main difference between reversible and irreversible inhibition lies in the extent to which an inhibitor binds to an enzyme and the effect this has on enzyme activity:

• Reversible Inhibition: In this case, the inhibitor binds to the enzyme through non-covalent, reversible interactions. This means that the inhibitor can dissociate from the enzyme, allowing the enzyme to regain its activity. Reversible inhibitors can be further classified into competitive and non-competitive inhibitors:
• Competitive inhibitors resemble the substrate structure and compete with the substrate for binding at the active site of the enzyme.
• Non-competitive inhibitors bind at a site distinct from the active site and do not compete with the substrate for the active site.
• Irreversible Inhibition: In this case, the inhibitor binds to the enzyme through a covalent bond, forming a strong, irreversible complex. This results in a permanent loss of enzymatic activity, as the inhibitor cannot be removed from the enzyme. Irreversible inhibitors often act through covalent modification of the enzyme, leading to a reduction in its activity.

In summary, the key differences between reversible and irreversible inhibition are:

• Reversible inhibitors bind through non-covalent interactions, while irreversible inhibitors bind through covalent interactions.
• Reversible inhibitors can be classified into competitive and non-competitive types, while irreversible inhibitors act through covalent modification.
• The effect of reversible inhibitors can be reversed by removing the inhibitor, while the effect of irreversible inhibitors is permanent.

Comparative Table: Reversible vs Irreversible Inhibition

The main difference between reversible and irreversible inhibition lies in the nature of the interaction between the inhibitor and the enzyme. Here is a table summarizing the differences:

Reversible inhibitors temporarily inhibit the action of an enzyme through non-covalent interactions, allowing the enzyme to regain its function once the inhibitor is removed. There are four types of reversible inhibition: competitive, uncompetitive, non-competitive, and mixed inhibition.

On the other hand, irreversible inhibitors permanently inhibit the enzyme function through covalent modifications. The dissociation of the enzyme-inhibitor complex takes a long time, preventing the enzyme from regaining its function.