| Assay Method Information | |
| | IMAP (immobilized metal ion affinity-based fluorescence polarization) assay |
| Description: | TBITK enzyme (Millipore #14-660M) is diluted to 0.2 U/mL in KR buffer (10 mM Tris-HCl, 10 mM MgCl2, 0.01% Tween-20, 0.1% NaN3, 1 mM DTT, 2 mM MnCl2, pH 7.5)Serial dilutions log 10 from 2 mM to 63.2 nM of test compounds are made in 100% DMSO. The dilutions in DMSO are then diluted 50-fold in KR-buffer. Final compound concentration range in the assay ranged from 10 μM to 0.316 nM.The assay is performed as follows: 5 μL/well of test compound in KR buffer (final DMSO concentration in the assay is 1%) is mixed with 5 μL/well of 0.2 U/mL ITK enzyme (final concentration in the assay is 0.05 U/mL (8.4 nM)). Test compounds and ITK enzyme are pre-incubated 60 minutes at room temperature, before adding 5 μL/well of 200 nM Fluorescin labeled substrate peptide (Blk/Lyntide substrate # R8124, Molecular Devices) in KR-buffer. Final peptide substrate concentration in assay is 50 nM. The kinase assay is started by adding 5 μL/well of 20 μM ATP in KR-buffer (final ATP concentration is 5 μM ATP, Km ATP in ITK IMAP assay). Following incubation for 2 hours at room temperature the enzyme reaction is stopped by adding 40 μL/well IMAP Progressive Binding Solution (according to suppliers (Molecular Devices) protocol using 60% 1× buffer A and 40% 1× buffer B with 800× diluted beads (Progressive Binding System, Molecular Devices # R8124). After 60 min incubation at room temperature in the dark the FP signal is read. Fluorescence at 535 nm is measured using parallel and perpendicular filters to determine differences in rotation due to binding of the phosphorylated substrate peptide to the beads. Values are calculated as percentage of the difference in readout (AmPi) of the controls with and without ATP. IC50 values are determined by curve fitting of the experimental results in Dotmatics.D |
| Affinity data for this assay | |
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