Measured by its binding ability in a functional ELISA. Immobilized human ACE2 protein (His tag) at 2μg/mL (100μL/well) can bind SARS-CoV-2 (2019-nCoV) Spike Protein (S1 Subunit, Fc Tag)(40591-V02H), the EC50 of SARS-CoV-2 (2019-nCoV) Spike Protein (S1 Subunit, Fc Tag) is 25-60 ng/mL.