Question

Which of the following is an example of a reversible inhibitor?

• A. DIPF
• B. Penicillin
• C. Iodoacetamide
• D. Protease inhibitors

Answer 1

The Correct Option is D

Enzyme inhibitors are typically categorized into two main types: reversible inhibitors and irreversible inhibitors, based on their binding interactions with enzymes. Reversible inhibitors bind temporarily and can be displaced, while irreversible inhibitors form covalent bonds that permanently alter enzyme activity.

 Step 1: Understanding Reversible Inhibitors - Reversible inhibitors interact with enzymes non-covalently, which means they can bind and dissociate without permanently changing the enzyme. - These inhibitors can be competitive, non-competitive, or uncompetitive, depending on how they interact with the enzyme and the substrate. - Protease inhibitors are commonly employed in pharmaceuticals and biological systems because they reversibly inhibit enzyme activity, such as in the case of viral proteases. 

Step 2: Evaluating the Options - Option (A) - Incorrect: DIPF (Diisopropyl fluorophosphate) is an irreversible inhibitor that covalently binds to the serine residues in enzymes, disrupting their activity permanently. - Option (B) - Incorrect: Penicillin is another irreversible inhibitor, specifically targeting bacterial transpeptidase by forming a covalent bond. - Option (C) - Incorrect: Iodoacetamide irreversibly modifies cysteine residues in proteins through covalent attachment. - Option (D) - Correct: Protease inhibitors act as reversible inhibitors by binding to enzymes, preventing them from processing substrates, but can be displaced when needed. 

Step 3: Conclusion Since protease inhibitors are reversible inhibitors, the correct answer is option (D).