The key difference between enzyme activator and enzyme inhibitor is that the enzyme activator can increase the activity of an enzyme whereas the enzyme inhibitor can decrease the activity of an enzyme.
Enzymes are proteins, and they consist of amino acids and are the biological catalysts. A catalyst is any compound that can decrease the reaction rate of a chemical reaction. Two types of compounds can affect the activity of enzymes; they are activators and inhibitors. Let us talk more details on these compounds.
CONTENTS
1. Overview and Key Difference
2. What is Enzyme Activator
3. What is Enzyme Inhibitor
4. Side by Side Comparison – Enzyme Activator vs Enzyme Inhibitor in Tabular Form
5. Summary
What is Enzyme Activator?
Enzyme activators are chemical species that can bind with an enzyme to increase its activity. Therefore, they can directly affect the activity of an enzyme. They act in the opposite way that the enzyme inhibitors are acting. Most of the times, they act by binding on to some regions, other than active sites of the enzyme. These are what we call “allosteric sites” of the enzyme.
Sometimes, the substrate or the reactant itself acts as the activator when this reactant binds with one active site of the enzyme. Therefore, it can increase in the enzyme’s affinity for substrates and activates other active sites as well. Some important examples of these molecules include hexokinase-I and glucokinase.
What is Enzyme Inhibitor?
Enzyme inhibitors are chemical species that can bind with an enzyme to decrease its activity. Therefore, they can directly affect the activity of an enzyme. They act in the opposite way that the enzyme activators are acting. Similarly, most of the inhibitors block the active sites of the enzyme. Thereby they can decrease the activity of the enzyme.
Figure 01: Binding of Inhibitors and Activators into the Allosteric site of an Enzyme
Sometimes, they bind to allosteric sites as well. The binding of this molecule can be either reversible or irreversible. In reversible binding, inhibitors are removed from the enzyme after blocking the binding of the substrate. On the contrary, in irreversible binding, inhibitors can alter the shape of the active site irreversibly. Therefore, no more substrates will bind with the active site of the enzyme. Some typical examples include drugs, ribonuclease inhibitor, etc.
What is the Difference Between Enzyme Activator and Enzyme Inhibitor?
Enzyme activators are chemical species that can bind with an enzyme to increase its activity. Therefore, they can affect the activity of an enzyme. Some common examples of enzyme activators include hexokinase-I and glucokinase. Enzyme inhibitors are chemical species that can bind with an enzyme to decrease its activity. Therefore, they can affect the activity of an enzyme in a decreasing manner. Hence, this is the key difference between enzyme activator and enzyme inhibitor. Some common examples of enzyme inhibitors include drugs, ribonuclease inhibitor, etc.
Summary – Enzyme Activator vs Enzyme Inhibitor
The activators and inhibitors are two molecules that can affect the activity of an enzyme. The difference between enzyme activator and enzyme inhibitor is that the enzyme activators can increase the activity of an enzyme whereas the enzyme inhibitors can decrease the activity of an enzyme.
Reference:
1. “Enzyme Activator.” Wikipedia, Wikimedia Foundation, 15 July 2018. Available here
2. “Enzyme Inhibitor.” Wikipedia, Wikimedia Foundation, 3 July 2018. Available here
Image Courtesy:
1.’Figure 06 05 05’By CNX OpenStax , (CC BY 4.0) via Commons Wikimedia