Angiotensin-converting enzyme (EC 18.104.22.168), or ACE, is a central component of the renin–angiotensin system (RAS), which controls blood pressure by regulating the volume of fluids in the body. It converts the hormone angiotensin I to the active vasoconstrictor angiotensin II. Therefore, ACE indirectly increases blood pressure by causing blood vessels to constrict. ACE inhibitors are widely used as pharmaceutical drugs for treatment of cardiovascular diseases.
The enzyme was discovered by Leonard T. Skeggs Jr. in 1956.
It is located mainly in the capillaries of the lungs but can also be found in endothelial and kidney epithelial cells.
Other less known functions of ACE are degradation of bradykinin and amyloid beta-protein.