ACE2 and severe acute respiratory syndrome: While ACE2, a type I transmembrane glycoprotein, serves as a functional receptor for SARS-CoV-2, ACE2 is also shown to play a protective role against acute respiratory distress syndrome (ARDS) and SARS pathogenesis by catalyzing angiotensin I and angiotensin II to angiotensin (1-9) and angiotensin (1-7), respectively (7).