Question

What is meant by inhibition of an enzyme? What happens when an enzyme is irreversibly inhibited?

Short answer

Enzyme inhibition refers to the process in which a molecule, called an inhibitor, binds to an enzyme, thus reducing or completely blocking its ability to catalyze its target reaction. Irreversible inhibition is a type of enzyme inhibition where the inhibitor forms a strong, stable chemical bond with the enzyme, often involving a covalent bond. This results in a structural change in the enzyme, permanently inactivating it. The consequences of irreversible inhibition can include buildup of intermediates, decreased production of necessary products, or activation/deactivation of other biochemical pathways. Irreversible enzyme inhibitors are sometimes used in drugs to target specific enzymes related to diseases.

Step-by-step solution

Define Enzyme Inhibition

Enzyme inhibition is a process where a molecule (inhibitor) binds to an enzyme, reducing or completely blocking its ability to catalyze its target reaction. Inhibited enzymes are less efficient or entirely unable to catalyze their target reactions, which can reduce the overall rate or stop a metabolic pathway or biochemical process.

Types of Enzyme Inhibition

There are two types of enzyme inhibition: reversible and irreversible. In reversible inhibition, the inhibitor can bind and unbind from the enzyme, allowing it to function when the inhibitor is not present. In irreversible inhibition, the binding of the inhibitor to the enzyme is permanent, causing a permanent loss of enzyme function.

Irreversible Enzyme Inhibition

Irreversible inhibition occurs when an inhibitor forms a strong, stable chemical bond with the enzyme. Usually, this involves a covalent bond between the inhibitor molecule and an amino acid residue in the enzyme's active site. This strong bond results in a structural change in the enzyme, often preventing the enzyme's substrate from binding to the active site. As a result, the enzyme is permanently inactivated and can no longer function.

Effects of Irreversible Inhibition

When an enzyme is irreversibly inhibited, it cannot catalyze its target reaction, which can have significant consequences for the cell and organism. Depending on the specific enzyme and metabolic pathway, this can lead to a buildup of one or more intermediates, a decrease in the production of a necessary product, or the activation or deactivation of other biochemical pathways. Irreversible enzyme inhibitors are sometimes used as drugs to target specific enzymes involved in diseases, such as antibiotics that target bacterial enzymes or medications that inhibit enzymes involved in cancer cell growth.