CHEMBL5737205

In Vitro Inhibition Assay: EnzymesRecombinant human DPPIV (R&D Systems, Cat. No. 1180-SE)Recombinant human DPP8 (Enzo Life Sciences, Cat. No. BML-SE527)Recombinant human DPP9 (R&D Systems, Cat. No. 5419-SE)Recombinant human DPPII (R&D Systems, Cat. No. 3438-SE)Recombinant human FAP (R&D Systems, Cat. No. 3715-SE)Recombinant human PREP (R&D Systems, Cat. No. 4308-SE)Assay Buffers25 mM Tris, pH 8.0 (DPPIV and DPP9)50 mM Tris, pH 7.5 (DPP8)25 mM MES, pH 6.0 (DPPII)50 mM Tris, 140 mM NaCl, pH 7.5 (FAP)25 mM Tris, 0.25 M NaCl, pH 7.5 (PREP)Substrates4000× substrate solution (100 mM Gly-Pro-AMC (VWR, Cat. No. 100042-646) in DMSO, DPPIV, DPP8 and DPP9)4000× substrate solution (100 mM Lys-Pro-AMC (Bachem, Cat. No. I-1745) in DMSO, DPPII)100× substrate solution (2.5 mM Z-Gly-Pro-AMC (VWR, Cat. No. I-1145.0050BA) in DMSO, FAP and PREP)General MaterialsCompound96-well black clear-bottom plates (Costar, Cat. No. 3603)InstrumentationPlate shakerMolecular Devices SpectraMax® M2e microplate readerProtocol1. To prepare the compound for the assay, dissolve it in either DMSO or, if cyclization is suspected, in pH 2.0 water (0.01 N HCl) to a final concentration of 100 mM. For pH 2.0 stocks, incubate at room temperature for a minimum of four hours and up to overnight. From this, prepare a 1 mM stock at pH 7.4 in 50 mM Tris. If the inhibitor is insoluble at this concentration, dilute the 100 mM stock 1:10 to 10 mM. Using this stock, prepare a 0.1 mM stock as described above.2. Prepare a dilution plate for the compound stocks to be tested. Add the 0.1 and/or 1 mM stocks prepared previously to row A of a 96-well plate. From this, perform 1:10 serial dilutions into the appropriate assay buffer down the columns as shown below:3. Prepare 20× substrate solution by diluting the DMSO stocks into the appropriate assay buffer.4. Dilute the enzymes into their appropriate assay buffers. The dilution factor is lot dependent and must be determined prior to performing the assay. The final enzyme concentrations should be 0.1, 0.8, 0.4, 0.2, 1.2, and 0.6 nM for DPPIV, 8, 9, II, FAP and PREP respectively. Add 180 μL to each well needed in columns 2-10.5. Add 20 μL of the compound of interest from the dilution plate prepared in step 2 to columns 2-10 of the assay plate where appropriate. Each sample should be tested in triplicate. Allow this to incubate for 10 minutes at room temperature, shaking the plate for the first two minutes.6. Add 10 μL of 20× substrate prepared in step 3 to each well and allow this to incubate for 15 minutes at room temperature, shaking the plate for the first two minutes.