| Assay Method Information | |
| | Analysis of Inhibition of HDAC9 with the Compounds |
| Description: | The potency of the compounds is quantified by measuring the Histone Deacetylase 9 (HDAC9) enzymatic activity using the fluorogenic substrate, Boc-Lys(Tfa)-AMC. The substrate is deacetylated to Boc-Lys-AMC by HDAC9. Cleavage by trypsin results in the release of the fluorophore AMC from the deacetylated substrate. The fluorescence of the sample is directly related to the histone deacetylase activity in the sample.Serially Dilute the Compounds.Serial dilutions of the compounds and control reference compound (1-(5-(3-((4-(1,3,4-oxadiazol-2-yl)phenoxy)methyl)-1,2,4-oxadiazol-5-yl)thiophen-2-yl)-2,2,2-trifluoroethanone) are made by first resuspending the lyophilized compound to a final concentration of 10 mM in 100% DMSO. Stocks of 60 μL aliquots of the 10 mM compound in DMSO are prepared and stored at −20° C. From one stock aliquot of each compound to be tested and the reference compound, a 16-point serial dilution is prepared according to Table 1 using a 125 μL 16-channel Matrix multi-channel pipette.2 μL (200×) of each diluted solution and each control (full activity: 100% DMSO alone or full inhibition 1 mM) is stamped into V-bottom polypropylene 384-well compound plates using either the Bravo, Janus, or 12.5 μL 16-channel Matrix multi-channel pipette. Each well with the stamped 200× compound solution is diluted 1:20 by the addition of 38 μL assay buffer+DMSO (10.5% DMSO, 45 mM Tris-HCl, 123 mM NaCl, 2.4 mM KCl, and 0.9 mM MgCl2 at pH 8.0 and equilibrated to 37° C.).Prepare HDAC9 Enzyme (0.57 μg/mL).The HDAC9 enzyme is human HDAC9 (GenBank Accession No. NM_178423) amino acids 604-1066 with a C-terminal His tag and can be obtained from BPS BioScience. The protein is 50.7 kDa and is expressed in a baculovirus expression system. A working solution of enzyme is prepared from a 0.5 mg/mL stock aliquot of HDAC9 (thawed on ice) diluted to 0.57 μg/mL with assay buffer (50 mM Tris-HCl, 137 mM NaCl, 2.7 mM KCl, and 1 mM MgCl2 at pH 8 and equilibrated to 37° C.) just prior to the addition of enzyme to the assay.Prepare 5× (125 μM) Boc-Lys(Tfa)-AMC Substrate.5× (125 μM) substrate is prepared just prior to the addition to the assay. The 5× substrate is prepared by diluting a 100 mM Boc-Lys(Tfa)-AMC in DMSO solution 1:800 by adding it drop-wise to assay buffer (equilibrated to 37° C.) while vortexing at slow speed to prevent precipitation.Prepare 3× (30 μM) Developer/Stop Solution.3× (30 μM) Developer/Stop Solution is prepared just prior to addition to the plate by diluting a stock solution of 10 mM reference compound 1:333 in 25 mg/mL trypsin equilibrated to 37° C.Assay.5 μL of each solution of 1:20 diluted compound from above is transferred to a clear bottomed, black, 384-well assay plate using the Bravo or Janus. Using a 16-channel Matrix multi-channel pipette, 35 μL of the working solution of the HDAC9 enzyme (0.57 μg/mL in assay buffer) is transferred to the assay plate. The assay is then started by adding 10 μL of 5× (125 μM) substrate to the assay plate using either the Bravo, Janus or 16-channel Matrix multi-channel pipette. The assay plate is then shaken for one minute on an orbital shaker at 900 rpm. Next, the plate is incubated for 15 minutes at 37° C. The reaction is stopped by adding 25 μL of 3× developer/stop solution to the assay plates using either the Bravo, Janus or a 16-channel Matrix multi-channel pipette. The assay plate is then shaken for 2 minutes on an orbital shaker at 900 rpm. Next, the assay plate is incubated at 37° C. for 1 hour in a tissue culture incubator followed by shaking for 1 minute at maximum rpm on an orbital shaker before reading on the enVision. Finally, the fluorescence is measured (Excitation: 355 nm, Emission: 460 nm) using PerkinElmer EnVision in top read mode. |
| Affinity data for this assay | |
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