CHEMBL5732022

TrkB Activity: Reagents and consumables were purchased from Sigma Aldrich, Carna Biosciences, or Caliper Life Sciences. All assay reaction conditions for IC50 determinations were within the linear range with respect to time and enzyme concentration. In a 384 well polypropylene plate, TrkB (0.6 nM, Carna 08-187) was pre-incubated in a 100 mM Hepes-NaOH pH 7.5 buffer containing 0.01% Triton X-100, 10 mM MgCl2, 0.1% BSA, 1 mM DTT, 10 uM sodium orthovanadate and 10 μM beta-glycerophosphate and compound with a concentration of 2.5% DMSO for 15 minutes at room temperature. The reaction was initiated with an equal volume of peptide substrate (Caliper Life Sciences catalog no. 760430) and ATP in the aforementioned buffer. The final concentrations in the reaction were 300 pM TrkB, 1.5 μM peptide substrate and 70 μM ATP (ATP Km). The reaction was incubated at room temperature for 180 minutes and terminated with a buffer containing excess EDTA (100 mM Hepes-NaOH pH 7.5, 0.02% Brij, 0.1% CR-3, 0.36% DMSO and 100 mM EDTA). The plate was run for one cycle on a LabChip 3000 (Caliper Life Sciences, Hopkinton, Mass.) in an off-chip mobility shift type assay with an upstream voltage of −2250 volts, a downstream voltage of −500 volts and a vacuum pressure of −1.6 psi. The LabChip 3000 separates and measures the fluorescent signal of fluorescein labeled peptide substrate and fluorescein labeled peptide product present in each well. Results are expressed as percent conversion by measuring peak height for both the substrate and product and dividing the product peak height by the sum of peak heights for both substrate and product. On every plate 100% inhibition (with a saturating concentration of staurosporine) and 0% inhibition (substrate with enzyme and DMSO) controls were used to calculate percent inhibition of tested compounds and a Z′prime value.