Table 1.

Kinetic Analysis of hACE2 Binding to SARS-CoV-2 S^B and SARS-CoV S^B by Biolayer Interferometry

	SARS-CoV-2 SB	SARS-CoV SB
KD (nM)	1.2 ± 0.1	5.0 ± 0.1
kon (M−1.s−1)	1.4 × 105 (2.3 ± 1.4 × 105)	1.4 × 105 (1.7 ± 0.7 × 105)
koff (s−1)	1.6 × 10−4 (1.7 ± 0.8 × 10−4)	7.1x 10−4 (8.7 ± 5.1 × 10−4)

Values reported represent the global fit to the data shown in Figures 2A and 2B and the averages obtained from five (SARS-CoV-2) or four (SARS-CoV) replicates carried out with different protein preparations are shown in parentheses.