Fig. 3: Enzymatic activity of soluble and membrane hACE2.

hACE2 activity in the presence of VHHs B07, B09, B10 or absence (-) was assayed using the SensoLyte 390 ACE2 Activity Assay Kit, which measures fluorogenic peptide cleavage. a Soluble hACE2 (sACE2) activity in the presence of 10 µM VHHs. An ACE2 inhibitor, provided with the kit, was used as control (DX600, 1 µM). Data are means ± SD of three independent experiments. Paired T test two-sided: ns, nonsignificant; ** p = 0.0053. b VHHs B07, B09, B10 were used at different doses (one representative experiment out of three performed in duplicates. Mean values of the duplicate). The mock control (buffer) was arbitrarily positioned at 10-14. c The ACE2 inhibitor DX600 was used at different doses. Data are means ± SD of seven independent experiments. The mock control (buffer) was arbitrarily positioned at 10-14. d Cell surface hACE2 activity in the presence of saturating concentration of VHHs ( > 20 µM) or 1 µM DX600. Data are means ± SD of four independent experiments. Paired T test two-sided: ns, nonsignificant; ** p = 0.0070. Source Data are provided as a Source Data file.