Inhibitory assays
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A panel of 10 kinases consisting of FAK, Flt3, JAK2, JAK3, CSF-1R, SRC, VEGFR3, Aurora A, LIMK1, and ROCK2 was initially used to evaluate kinase inhibition profiles. 15 μL assay reactions were performed in Greiner brand white 384-well, low-volume plates. All reactions contained assay buffer (10 mM HEPES pH 7.4, 10 mM MgCl2, 0.01% (v/v) Tween-20, 50 μM Na3VO4, 0.01% (w/v) albumin from chicken egg white, 1 mM dithiothreitol), a N-terminally biotinylated peptide substrate (concentration 111 nM), and ATP at a concentration equaling the KM (ATP) of the kinase. The compounds were added in a volume of 100 nL from an 11-point-dilution series prepared in DMSO, positive and negative control reactions receiving the same volume of DMSO without compound. The kinases were added at predetermined concentrations, generally ranging between 0.2 and 8 nM, with the enzyme being omitted from negative control reactions. The reactions were incubated for 90 min at 30 °C and stopped by adding 5 μL of Stop buffer (10 mM HEPES pH 7.4, 25 mM NaCl, 100 mM EDTA, 0.01% (v/v) Tween-20) containing streptavidin-coated donor and antiphosphotyrosine (P-Tyr-100) acceptor beads. Plates were incubated for 4–6 h before being read on a PerkinElmer EnVision plate reader in HTS Alphascreen mode.
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Applications
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CTX-0294885 exhibited inhibitory activity against a broad range of kinases in vitro, and further developed it into a Sepharose-supported kinase capture reagent. Large-scale CTx-0294885-based affinity purification followed by LC-MS/MS led to the identification of 235 protein kinases from MDA-MB-231 cells, including all members of the AKT family that had not been previously detected by other broad-spectrum kinase inhibitors.
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References:
[1]. Zhang L, Holmes I P, Hochgrafe F, et al. Characterization of the novel broad-spectrum kinase inhibitor CTx-0294885 as an affinity reagent for mass spectrometry-based kinome profiling[J]. Journal of proteome research, 2013, 12(7): 3104-3116.
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