Recombinant Human ACE2-Fc-Avi Protein (rhACE2-Fc)

Source: recombinant human ACE2 protein (Gln18-Ser740) was expressed in mammalian cells with a Fc fusion and Avi at the C-terminus.Accession: Q9BYF1Predicted molecular mass: 111.2 kDa. Due to glycosylation, the rhACE2 protein migrates to 115-125 kDa based on the Bis-Tris PAGE result.Endotoxin: Less than 0.5 EU per ug by the LAL method.Activity: Immobilized biotinylated recombinant SARS-CoV-2 Spike S RBD with the His Tag at 1 ug/ml (100 ul/well). Dose response curve for rhACE2-Fc fusion protein with the EC50 of 81 ng/ml determined by ELISA. Conditions of optimal recombinant Human ACE2 protein (rhACE2-Fc) performance should be determined experimentally by the investigator.Formulation: The recombinant human ACE2-Fc-Avi protein was lyophilized from 0.22 um filtered solution in 20 mM PB (pH 7.4). Normally 5% trehalose is added as protectant before lyophilization.Purity: > 95% by PAGE under reduced condition, and SEC-HPLC.Shipping: The recombinant human ACE2-Fc-Avi protein is shipped with ice packs. Upon receipt, store it immediately at the temperature recommended below.Stability & Storage:Use a manual defrost freezer and avoid repeated freeze-thaw cycles.12 months from date of receipt, -20 to -70°C as supplied.1 month, 2 to 8°C under sterile conditions after reconstitution.3 months, -20 to -70°C under sterile conditions after reconstitution.

Background

ACE2 (Angiotensin I Converting Enzyme 2) belongs to the angiotensin-converting enzyme family of dipeptidylcarboxydipeptidases and has considerable homology to human angiotensin 1 converting enzyme. This secreted protein catalyzes the cleavage of angiotensin I into angiotensin 1-9, and angiotensin II into the vasodilator angiotensin 1-7. Diseases associated with ACE2 include Severe Acute Respiratory Syndrome (SARS) including Coronavirus Disease 2019 (COVID-19), and Neurogenic Hypertension. The SARS-CoV and SARS-CoV-2 (2019-nCoV) spike (S) proteins mediate viral entry into host cells by binding to the ACE2 receptor through the receptor-binding domain (RBD) of the S1 subunit, and then fusing the viral and host membranes through the S2 subunit. The ACE2-binding affinity of the Spike RBD of SARS-CoV-2 is 10- to 20-fold higher than that of SARS-CoV. Two trimeric SARS-CoV-2 spike proteins bind to an ACE2 dimer with the collectrin-like domain of ACE2 mediating homodimerization.

The binding of the S1 subunit to the extracellular peptidase domain of ACE2 on the surface of cells results in endocytosis and translocation of both the virus and the enzyme into endosomes located within cells. This entry process also requires priming of the S protein by the host serine protease TMPRSS2, which is a potential drug for inhibition. The recombinant human ACE2 (rhACE2) may also be a promising drug for those with intolerance to classic renin-angiotensin system inhibitors (RAS inhibitors) or in diseases where circulating angiotensin II is elevated. Infused rhACE2 has been evaluated in clinical trials for the treatment of SARS.