Enzyme Inhibition

Introduction

Inhibitors that do not contribute to the development of the product carry out the inhibition. The inhibitors can impact both the substrate and the enzyme. The stoppage of enzyme activity is referred to as enzyme inhibition.

These enzyme inhibitors can attach to active areas and halt or inhibit further activity. This form of binding can be both reversible and irreversible.

Table of Contents

• Types of Enzyme Inhibition
• Competitive Inhibition
• Non-competitive Inhibition
• Uncompetitive Inhibition
• Applications of Enzyme Inhibition
• Frequently Asked Questions – FAQs

Types of Enzyme Inhibition

Depending on the specific action of the inhibitor used, enzyme inhibition might be reversible or irreversible. Enzyme inhibitors can block the binding site, preventing the substrate from attaching to the active site, and decreasing the enzyme’s catalytic activity.

Reversible inhibitors attach to enzymes via non-covalent interactions like hydrogen bonds, hydrophobic contacts, and ionic bonds. When attached to an enzyme, reversible inhibitors do not undergo chemical reactions and can be easily eliminated by dilution or dialysis.

On the other hand, irreversible inhibitors frequently covalently alter an enzyme, preventing the reversal of inhibition.

There are three types of enzyme inhibition reactions.

1. Competitive Inhibition
2. Non-competitive Inhibition
3. Uncompetitive Inhibition

Competitive Inhibition

A molecule other than the substrate binds to the enzyme’s active site, causing competitive inhibition. The inhibitor (molecule) has a structural and chemical similarity to the substrate (hence able to bind to the active site). The competitive inhibitor hinders substrate binding by blocking the active site. Since the inhibitor competes with the substrate, increasing the substrate concentration reduces the inhibitor’s actions.

Non-Competitive Inhibition

A chemical binds to a location other than the active site in non-competitive inhibition (an allosteric site). When the inhibitor binds to the allosteric site, the enzyme’s active site undergoes a structural shift. The active site and substrate no longer share affinity as a result of this alteration, preventing the substrate from binding. Increased substrate levels will not be able to reverse the inhibitor’s action since the inhibitor is not in direct competition with the substrate.

Uncompetitive Inhibition

The inhibitor binds only to the substrate-enzyme complex in uncompetitive inhibition. In reactions involving two or more substrates or products, uncompetitive inhibition is common. Non-competitive inhibition can occur with or without the presence of the substrate, whereas uncompetitive inhibition requires the formation of an enzyme-substrate complex.

Applications of Enzyme Inhibition

In the pharmaceutical and medical industries, enzyme inhibitors are essential. Pharmacologists benefit from a basic grasp of inhibitor activity during the development of new therapeutic medicines.

Insecticides such as malathion, herbicides such as glyphosate, and disinfectants such as triclosan are all examples of artificial inhibitors. Other synthetic enzyme inhibitors inhibit acetylcholinesterase, an enzyme that breaks down acetylcholine, and are utilised in chemical warfare as nerve agents.