| Assay Method Information | |
| | ITK Enzyme Assay |
| Description: | 1.0M HEPES Buffer pH 7.5 solution was prepared as follows: 238.3 g HEPES free acid (Sigma) and 800 mL of water were combined, and the mixture was stirred until complete dissolution. The pH was adjusted to 7.5 via titration with 5N NaOH and the volume adjusted to 1000 mL. The solution was filtered and sterilized. ITK assay buffer was prepared as follows: 50 mL of HPLC-grade water was treated with 2 mL of 1.0M HEPES Buffer, 500 μL of 2% Gelatin (Sigma), 1.0 mL of aqueous MgCl2 solution (1.0M), and 1.0 mL of aqueous glutathione solution (0.5M), and the solution was mixed. The solution was brought to 99 mL in a graduated cylinder by addition of water and sterilized through a 0.2 μm filter. 0.1 mL of Brij-35 Surfact-Amps Detergent Solution (10% w/v aqueous solution, ThermoFisher) and 1.0 mL of ATP (Teknova,100 mM) were added and the solution was mixed. Preparation of 1.33× ITK enzyme solution was as follows: 49.99 mL of ITK assay buffer was treated with 4.1 μL of ITK enzyme (ITK FL (N-Flag and C-His tagged, 72 kDa) Lake Pharma, 0.25 mg/ml in a buffer containing 25 mM Tris pH 7.8, 150 mM NaCl, 10% glycerol and 2 mM TCEP) and the mixture was gently agitated. The resulting solution was stored on ice. 30 Minutes prior to use, the enzyme solution was removed from ice and equilibrated to RT by incubation in a RT water bath. Preparation of 4× ITK substrate solution was as follows: 50 mL of ITK assay buffer was treated with 100 μL of BTK peptide (China Peptide Company, 2 mM stock solution in DMSO). The tube was capped, mixed by gently inverting the tube, and then stored on ice. 30 Minutes prior to use, the substrate solution was removed from ice and equilibrated to RT by incubation in a RT water bath.At the time of assay, 7.5 μL of the 1.33× ITK enzyme solution was added to plate wells containing 0.1 μL of varying concentrations of test compound in DMSO. The plate was incubated 30 min at RT. The plate wells were each treated with 2.5 uL of the 4× ITK substrate solution and the plate was sealed (TopSeal , Perkin Elmer). The plate was spun at 1000 rpm for 30 sec and then incubated for 60 min at RT. The seal was removed, and each well was treated with 10 μL of Stop/Detect Buffer (20 mM HEPES pH 7.5, 0.01% gelatin, 1 nM LANCE PT66 (Perkin Elmer), 16.5 μg/ml Surelight APC (Perkin Elmer), 10 mM EDTA, 250 mM NaCl). The plate was again covered and was spun at 1000 rpm for seconds. The plate was allowed to incubate overnight at RT and in a closed carrier to reduce dehydration. |
| Affinity data for this assay | |
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