INI-CET 2021 — Biochemistry

Question 11: Identify the false statement regarding suicide inhibition

• A. The binding of the enzyme to the substrate analogue is irreversible
• B. The inhibitor forms a product with the enzyme and the product inhibits it
• C. The inhibitor can bind with any site resulting in suicidal inhibition (Correct Answer)
• D. They are enzyme specific and used in rational drug design

Explanation: ***The inhibitor can bind with any site resulting in suicidal inhibition*** - Suicide inhibition, also known as **mechanism-based inhibition**, is highly specific and requires the inhibitor to bind to the **active site** of the enzyme. - The enzyme then catalyzes a transformation of the inhibitor into a **reactive intermediate** that irreversibly binds to the active site. *The binding of the enzyme to the substrate analogue is irreversible* - This statement is true; once the suicide inhibitor is metabolically activated by the enzyme, it forms a **covalent bond** with a residue in the active site. - This irreversible binding permanently inactivates the enzyme. *The inhibitor forms a product with the enzyme and the product inhibits it* - This statement is true; the enzyme's catalytic action converts the inhibitor (a substrate analogue) into a **highly reactive compound**. - This reactive product then binds covalently and irreversibly to the enzyme's **active site**, leading to its inactivation. *They are enzyme specific and used in rational drug design* - This statement is true; suicide inhibitors are designed to be highly specific for a particular enzyme, as they rely on that enzyme's catalytic mechanism for their activation. - Their specificity and irreversible action make them valuable tools in **drug discovery** and **rational drug design**, allowing for targeted inactivation of disease-related enzymes.