Table 3.
Fluorescence Extinction Coefficients (FECs) of various FRET-peptide substrates and their activity with SARS-CoV 3CLpro
| 1 FRET-Peptide Substrate | 2 FEC (AFU/μM) | 3 Activity (min−1) |
|---|---|---|
| Alexa488-QSY7 | 37,840 ± 15 | 0.038 |
| Alexa594-QSY21 | 3,350 ± 100 | 0.003 |
| Dabcyl-Edans | 4,530 ± 150 | 0.068 |
| Abz-Tyr(NO2) | 830 ± 50 | 0.028 |
1
The specific sequence for each FRET-peptide substrate is described in Materials and Methods
2
The fluorescence extinction coefficient values (FECs) were determined from the slope of the line that was fit to the data in Figure 4. The slope, or FEC value, resulted from a fit of the data to a line using linear regression.
3
The activity i.e. turnover number was determined at a substrate concentration of 1 μM and a non-tagged enzyme concentration of 100 nM.