CHEMBL5737034

Measurement of Inhibition of MPS1 Kinase: The enzyme reaction (total volume 10 μl) was carried out in black 384-well low volume plates containing full length MPS1 (12.5 nM or 3 nM), fluorescent labelled peptide [known as H236, which has the sequence: 5FAM-DHTGFLTEYVATR-CONH2] (5 μM), ATP (10 μM), either DMSO (1% v/v) or the test compound (in the range 0.25 nM-100 μM in 1% DMSO) and assay buffer (50 mM HEPES (pH 7.0), 0.02% NaN3, 0.01% BSA, 0.1 mM Orthovandate, 10 μM MgCl2, 1 μM DTT, Roche protease inhibitor). The reaction was carried out for 60 min at room temperature and stopped by the addition of buffer (10 μl) containing 20 mM EDTA, 0.05% (v/v) Brij-35, in 0.1M HEPES-buffered saline (Free acid, Sigma. UK). The plate was read on a Caliper EZ reader II (Caliper Life Sciences).The reader provides a Software package (‘Reviewer’) which converts the peak heights into % conversion by measuring both product and substrate peak and also allows selection of control well which represent 0% and 100% inhibition, respectively. The % inhibition of the compounds is calculated relative to the means of selected control wells. IC50s are determined by testing the compounds at a range of concentrations from 0.25 nM-100 μM. The % inhibitions at each concentration are then fitted to a 4 parameter logistic fit:y=(a+((b−a)/(1+((c/x{circumflex over ( )}d))))where a=asym min, b=asym max, c=IC50 and d=hill coefficient.