Abstract: The rennin angiotensin system had been recognized for many years as a key regular of systemic blood pressure and the metabolism of water and salt. Angiotensin converting enzyme 2(ACE2) was the first human homolog of Angiotensin converting enzyme which efficiently hydrolyzed the angiotensin II to vasodilator angiotensin l-7.ACE2 is now implicated in cardiovascular ,renal, lung disease and serves as a receptor for Severe Acute Respiratory Syndrome coronavirus.