MK-3697, an isonicotinamide small molecule, acts as a potent and selective Orexin 2 receptor antagonist (Ki: 0.95 nM).

Cyclin/CDK kinase assay: Recombinant cyclin/CDK holoenzymes are purified from Sf9 cells engineered to produce baculoviruses that express a specific cyclin or CDK. Cyclin/CDK complexes are typically diluted to a final concentration of 50 μg/mL in a kinase reaction buffer containing 50 mM Tris-HCl (pH 8.0), 10 mM MgCl2, 1 mM DTT, and 0.1 mM sodium orthovanadate. For each kinase reaction, 1 μg of enzyme and 20 μL of a 2-μM substrate solution (a biotinylated peptide derived from histone H1) are mixed and combined with 10 μL of diluted Dinaciclib. The reaction is started by the addition of 50 μL of 2 μM ATP and 0.1 μCi of 33P-ATP. Kinase reactions are incubated for 1 hour at room temperature and are stopped by the addition of 0.1% Triton X-100, 1 mM ATP, 5 mM EDTA, and 5 mg/mL streptavidin-coated SPA beads. SPA beads are captured using a 96-well GF/B filter plate and a Filtermate universal harvester. Beads are washed twice with 2 M NaCl and twice with 2 M NaCl containing 1% phosphoric acid. The signal is then assayed using a TopCount 96-well liquid scintillation counter.