Angiotensin-Converting Enzyme 2 (ACE-2) is an integral membrane protein and a zinc metalloprotease of the ACE family which includes somatic and germinal ACE. ACE-2 cleaves angiotensins I and II as a carboxypeptidase and converts angiotensin I to angiotensin 1-9, and angiotensin II to angiotensin 1-7. ACE-2 is also able to hydrolyze apelin-13 and dynorphin-13 with high efficiency. ACE-2 can be highly expressed in testis, kidney, heart, colon, small intestine and ovary at moderate levels. ACE2 is not inhibited by the classical ACE inhibitors, captopril and lisinopril and may play an important role in regulating the heart function.