Figure 6. Estimating affinity from efficacy.
If η and E0 are known, EC50 can be calculated from the maximum response. A. Log-log plot of EC50 values calculated from POmax (Eq. 7) versus EC50 values estimated by fitting CRCs (Eq. 1), with linear fit (slope=1.08, R2=0.85). red, η=52% agonists and blue, η=40% agonists (Fig. 4). B. CRCs calculated from POmax (lines) superimpose approximately on experimental PO measurements (symbols).