ACE2 and COVID-19: Angiotensin-converting enzyme 2 (ACE2) is a type I transmembrane glycoprotein composed of 805 amino acids, and its amino acid sequence has 42% homology with ACE.[1] ACE2 is a receptor that antagonizes the RAS system,[2] which is highly expressed in islet cells and the exocrine pancreas, and is closely related to the susceptibility of diabetic patients to COVID-19.