Description：Recombinant COVID-19 S2 Protein is produced by mammalian expression system and the target gene encoding Ser686-Gln1208 is expressed with a Fc tag at the C-terminus.Form：Liquid in a 0.2 μm filtered solution of PBS, pH 7.4.Alternative Names：S2 protein; Spike glycoprotein Subunit2; S glycoprotein Subunit2; Spike protein S2; COVID-19 Entrez Gene (Human)： QHD43416.1; Purity：Greater than 95% as determined by reducing SDS-PAGE.Directions for Use：Please minimize freeze-thaw cycles.Quality Control：Endotoxin: Less than 0.1 ng/µg (1 IEU/µg) as determined by LAL test.Storage/Stability：Store it at -20°C to -80°C for one year. It is recommended that the protein be aliquoted for optimal storage. Avoid repeated freeze-thaw cycles.