| Assay Method Information | |
| | Human DPP 1 Enzyme IC50 Assay |
| Description: | Table 3: Recombinant human DPP1 enzyme (R&D Systems; Minneapolis, MN) was first proteolytically processed into its mature form using recombinant human cathepsin L (R&D Systems) in a buffer consisting of 20 mM citric acid pH 4.5, 150 mM NaCl, 1 mM EDTA and 10 mM DTT. Test articles were applied to activated human DPP1 enzyme in Assay Buffer (25 mM MES pH 6.0, 50 mM NaCl, 5 mM DTT) in a total reaction volume of 125 μL. 25 μL of compound in Assay Buffer plus 5% DMSO was first added to 50 μL of activated human DPP1 enzyme at a concentration of 1 ng/μL and allowed to pre-incubate for 10 minutes at 37° C. after which 50 μL of 1000 μM H-Gly-Arg-AMC substrate (Bachem; St. Torrance, CA) was added, giving final substrate concentration of 400 M and a final DMSO concentration of 1%. Substrate cleavage was measured for 90 minutes at 37° C., with fluorescence at Excitation/Emission 350/450 nm measured every 5 minutes. DPP1 concentration was interpolated based on its activity relative to a standard curve of activated human recombinant DPP1 enzyme. IC50 values for each compound were calculated via the XLFit (IDBS Version 5.3.1.3) Add-On to Microsoft Excel using the four parameter fit equation y={A+[(B−A)]/[1+((C/x){circumflex over ( )}D)]}, which appears as equation number 205 (4 Parameter Logistic Model or Sigmoidal Dose-Response Model) in XLFit. Default constraints were used for each Parameter. IC50 was defined as the compound concentration at which 50% of enzyme activity was inhibited when compared to the no-compound control. |
| Affinity data for this assay | |
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