The structure of one of the first ACE inhibitors is given below. What is the purpose of the sulfur in this molecule?
A) It is highly reactive with angiotensin II.
B) It binds to a metal on the exterior of ACE.
C) It holds the molecule in the active site of ACE.
D) It makes Captopril into a strong acid.
E) It forms a covalent bond with ACE, permanently deactivating it.

Question

The structure of one of the first ACE inhibitors is given below. What is the purpose of the sulfur in this molecule? 
A) It is highly reactive with angiotensin II. 
B) It binds to a metal on the exterior of ACE. 
C) It holds the molecule in the active site of ACE. 
D) It makes Captopril into a strong acid. 
E) It forms a covalent bond with ACE, permanently deactivating it.

Quizplus · Accepted Answer

The sulfur in this molecule is part of a thiol group, which is known to bind covalently with metal ions, such as zinc in the active site of ACE. This enables the inhibitor to hold the molecule in the active site of ACE, thereby preventing it from cleaving angiotensin I to angiotensin II.

The Structure of One of the First ACE Inhibitors Is