Angiotensin Converting Enzymes (ACE) are the part of renin angiotensin system mechanism [ 1 ]. The renin-angiotensin system plays critical roles in maintaining normal cardiovascular functions and contributes to a spectrum of cardiovascular diseases [ 2 ]. ACI Inhibitors and Angiotensin Receptor Blockers are used for the therapy of hypertension, hearth failure, myocardial infarction and diabetic nephropathy [ 3 ]. It is important to know that these ACE Inhibitors and Angiotensin Receptor Blockers (ARBs) are developed and utilized, from the time when the knowledge of structure of human ACE are not known. These Inhibitor and Blocker molecules are instead, initially designed based on assumed mechanical homology with carboxypeptidase A. At present the X-Ray structure of human ACE are available.