Description：Recombinant COVID-19 S1 Protein C-terminal domain is produced by mammalian expression system with a 8His; Flag tag at the N-terminus.Form：Liquid in a 0.2 μm filtered solution of PBS, pH 7.4.Alternative Names：S1 protein; 2019-nCoV S1 protein; coronavirus S1 Protein; cov S1 Protein 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.