Quantitative chemical proteomics was performed to profile the target proteins of ITCs.For the forward SILAC experiment, heavy-labeled cells were treated with the ITC probe (20 μM) for 30 min and light-labeled cells were pre-treated with the natural ITC (60 μM) for 30 min, followed by the ITC probe (20 μM) for another 30 min. For the reverse SILAC experiment, light-labeled cells were treated with the ITC probe (20 μM) for 30 min and heavy-labeled cells were treated with the natural ITC (60 μM) for 30 min, followed by the ITC probe (20 μM) for another 30 min.