ACE2 and infection: During infection, SARS-CoV-2, an enveloped virus containing one positive-strand RNA genome of 29.9 kb, gains entry to human epithelial cells by using spike proteins on its surface to bind angiotensin-converting enzyme 2 (ACE2).18 ACE2 is expressed on the surface of many types of cells in the human body, including in the heart, gut, lungs, and nasal mucosa.