ardiovascular disease, particularly arterial hypertension and congestive heart failure. At present, ACE inhibitors are among the most widely prescribed drugs worldwide. In 2000 a novel ACE-like enzyme, eventually named ACE2, was discovered. It showed a different substrate selectively, and in particular it could not activate angiotensin I. At the same time, it was not a target of classical ACE inhibitors. Investigations were therefore started, aiming at determining