Fig. (4). TEV Protease Titration TEV protease dose dependent activation of CP₂₃₄-Luc/ENLYFQS protein. Cell-free translation reactions were diluted 1:1 in 2X TEV protease buffer, incubated at 30°C for 30 minutes with titrating amounts of TEV protease and luminescence was measured from 5 µL aliquots in 100 µL 1:1 diluted Bright Glo^TM Luciferase Assay reagent in dH₂O; N = 4. Results are plotted as signal to noise (S/N). The limit of detection was defined as the amount of TEV protease giving a S/N ratio = 3 (dotted line). The R² value was 0.99.