Angiotensin-converting enzyme 2 (ACE2) and COVID-19 Sarina Sodha Grade 12, University of Toronto Schools, Toronto, On. Canada November 1, 2022

SARS-CoV-2 is the virus responsible for the COVID-19 pandemic which has resulted in over 609 million infections and 6.52 million deaths (Our World In Data, 2022). The angiotensin-converting enzyme 2 (ACE2) is the receptor for SARS-CoV-1 and SARS-CoV-2, allowing their spike (S) glycoproteins to bind to the surface of human cells (Chen et al., 2021). ACE2 is a type I transmembrane glycoprotein and zinc metallopeptidase containing 805 amino acids that can be found on the plasma membrane on many cell types within the body. The ACE2 protein is coded by the ACE2 gene which is located on chromosome Xp22 and is theorized to have evolved from ACE, due to their 42% shared sequence homology (Chen et al., 2021). Two functional forms of the ACE2 protein are expressed: the full length protein and its soluble counterpart (sACE2). Soluble ACE2 is formed by the shedding of the full-length ACE2 through metalloproteinase 17 (ADAM17). Unlike the soluble form, the full length ACE2 protein contains an extracellular transmembrane domain, connected to the plasma membrane (Chen et al., 2021).