ACE-2

Angiotensin I Converting Enzyme (ACE2) is a dimeric, zinc-dependent metalloprotease of the ACE family. ACE2 has been established as the functional host receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) . ACE2 is abundantly expressed in a variety of cells residing in many different human organs. In human physiology, ACE2 is a pivotal counter-regulatory enzyme to ACE by the breakdown of angiotensin II, the central player in the renin-angiotensin-aldosterone system (RAAS) and the main substrate of ACE2. Full length ACE2 protein includes an extracellular region composed of a single N-terminal peptidase domain and C-terminal collectrin-like domain (CLD), a transmembrane domain, and a short cytoplasmic tail. The N-terminal peptidase region is required for binding to SARS-CoV and SARS-CoV2 spike proteins, while the CLD contains a region that promotes dimerization and association with amino acid transporters. The peptidase domain contains a long deep cleft that undergoes a large hinge-bending movement at substrate and inhibitor binding. Classical ACE inhibitors such as captopril and lisinopril do not inhibit ACE2 activity and inhibitors of ACE2 do not inhibit ACE activity. The recombinant sACE2 consists of the extracellular domain from Gln18 to Asn639 and was fused at the C terminus to the human Fc-tag.