Angiotensin-converting enzyme (ACE) is important for blood pressure homeostasis through generation of the vasoconstrictor angiotensin II and inactivation of the vasodilatator bradykinin. ACE is a carboxyl-terminal dipeptidyl exopeptidase which converts angiotensin I to the potent vasopressive hormone angiotensin II. There are two isoforms of ACE, the pulmonary ACEP and the testicular ACET. ACEP is a 140 kDa glycoprotein widely expressed in vascular endothelial cells. ACET is a 100 kDa protein expressed exclusively in adult testis by developing sperm cells.