Experiments were performed with ITC200 instrument (Malvern) in 100 mM HEPES pH 7.5, 50 mM NaCl, 0.5 mM TCEP at 298 K. The ITC titration consisted of 0.4 μl initial injection (discarded during data analysis) followed by 19 of 2 μl injections at 120 s interval between injections. 1 mM of the ligands in 2-4% DMSO were titrated into 100 μM SBC. The GHR_pY595 peptide sequence was used for the ITC run -PVPDpYTSIHIV-amide . For the competition run, 1 mM GHR_pY595 was titrated into 100 μM SBC that was preincubated with 200 μM MN551 at room temperature for 2 hours. Binding data was subtracted from a control titration where ligand was titrated into buffer, and 8itted using a one-set-of-site binding model to obtain dissociation constant (Kd), binding enthalpy (ΔH), and stoichiometry (N) using MicroCal PEAQ-ITC Analysis Software1.1.0.1262 and MicroCal ITC-ORIGIN Analysis Software 7.0 (Malvern).