Angiotensin-converting enzyme (ACE) has an important role in the metabolism of several peptides and proteins, including chemical messengers, such as angiotensin I and bradykinin. The importance assumed by research focused on ACE biochemistry, physiology and pharmacology is closely linked to the clinical effectiveness showed by ACE inhibitors in the treatment of cardiovascular disease, particularly arterial hypertension and congestive heart failure. At present, ACE inhibitors are among the most widely prescribed drugs worldwide.