Figure 2.

Enzymatic activity of shed ACE2. A, Maintenance medium for 832/13 cells and select culture broths from the experiments outlined in Figure 1 were tested for hydrolytic activity against the ACE2 substrate Mca-APK(Dnp) in the absence and presence of the ACE2-specific inhibitor DX600. B, The ACE2 activities of 832/13 maintenance medium stored at 4°C, after an overnight incubation at 37°C, and after an overnight incubation with untransfected 832/13 cells at 37°C, were compared by measuring six aliquots of each. C, The ACE2 activities of the cell culture media from the experiments outlined in Figure 1 were determined. **,***, P < .01, P < .001 vs 0 μg pAd17; #, ###, P < .05, P < .001 vs 0.5 μg pAd17 for post hoc contrasts of means after an ANOVA.