CHEMBL5736668

Allosteric Inhibition Assay: SHP2 is allosterically activated through binding of bis-tyrosyl-phosphorylated peptides to its Src Homology 2 (SH2) domains. The latter activation step leads to the release of the auto-inhibitory interface of SHP2, which in turn renders the SHP2 protein tyrosine phosphatase (PTP) active and available for substrate recognition and reaction catalysis. The catalytic activity of SHP2 was monitored using the surrogate substrate DiFMUP in a prompt fluorescence assay format.More specifically, the phosphatase reactions were performed at room temperature in 384-well black polystyrene plate, flat bottom, low flange, non-binding surface (Corning, Cat #3575) using a final reaction volume of 25 μL and the following assay buffer conditions: 60 mM HEPES, pH 7.2, 75 mM NaCl, 75 mM KCl, 1 mM EDTA, 0.05% P-20, 5 mM DTT.The inhibition of SHP2 by compounds of the invention (concentrations varying from 0.003-100 μM) was monitored using an assay in which 0.5 nM of SHP2 was incubated with of 0.5 μM of peptide IRS1_pY1172(dPEG8)pY1222 (sequence: H2N-LN(pY)IDLDLV(dPEG8)LST(pY)ASINFQK-amide) (SEQ ID NO:1). After 30-60 minutes incubation at 25° C., the surrogate substrate DiFMUP (Invitrogen, cat #D6567) was added to the reaction and incubated at 25° C. for 30 minutes. The reaction was then quenched by the addition of 5 μl of a 160 μM solution of bpV(Phen) (Enzo Life Sciences cat #ALX-270-204). The fluorescence signal was monitored using a microplate reader (Envision, Perki-Elmer) using excitation and emission wavelengths of 340 nm and 450 nm, respectively. The inhibitor dose response curves were analyzed using normalized IC50 regression curve fitting with control based normalization.