Figure 1. Schematic of our approach to deconvolute protein targets on the basis of dose-response curves.

Drug X binds two protein targets with different affinities. Drug X binds the primary target (target 1) with high affinity. Thus, the accumulation of substrate 1 (S1) and the depletion of product 1 (P1) occurs at low concentrations of drug. In contrast, drug X binds the off-target protein (target 2) with low affinity. The accumulation of substrate 2 (S2) and the depletion of product 2 (P2) occurs only at high concentrations of drug. See Figure S1 for an experimental example of the same schematic