The interaction between the enantiomers of chloroquine (CQ) and hydroxychloroquine (HCQ) with the angiotensin-converting enzyme 2 (ACE2) is crucial in the search for effective therapies against COVID-19, given that ACE2 acts as a specific receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), facilitating its entry into host cells. The gene discussed is ACE2; the disease is COVID-19.