S-[3-(N-(Ethyl-d5)maleimide)] Captopril is deuterium labeled S-[3-(N-Ethylmaleimide)] Captopril (E922015). S-[3-(N-Ethylmaleimide)] Captopril is a related compound of Captopril (C175750), which is a competitive inhibitor ofangiotensin-converting enzyme (ACE) that convertsangiotensin I (AT I) to angiotensin II (AT II).Captopril can be used to treathypertension.