The human Angiotensin-Converting Enzyme 2 (hACE2) is a type I transmembrane metallocarboxypeptidase with homology to ACE, a regulator in the Renin-Angiotensin system (RAS) and long-known as a target for the treatment of hypertension. hACE2 is highly expressed at the surface of cells of the human lungs, arteries, kidneys, heart and intestine – all tissues shown to harbor SARS-CoV. The function of ACE2 is known as controlling blood pressure. This is accomplished by the hydrolysis of a small peptide hormone called Angiotensin II into the nonapeptide Angiotensin 1-9, which is thereafter converted into the heptapeptide angiotensin 1-7 by ACE and other endopeptidases. Angiotensin 1-7 acts in a vasoconstricting manner and is believed to be one of the main effectors in controlling the blood pressure and is therefore involved in pathophysiological processes like diabetes, hypertension and cardiac function in general. Recently it became known, that the new Coronavirus SARS-CoV-2 uses ACE2 as the entry point into alveolar cells of the lungs, where it replicates and causes the Coronavirus disease (COVID-19).
