CHEMBL5738707

DPP9 Enzymatic Activity Assay: DPP9 enzymatic activity assay. To assay baseline dipeptidyl peptidase 9 (DPP9) activity, 40 ng of recombinant human DPP9 (rhDPP9) (R&S system, #5419-SE) was incubated with 100 μM of H-Gly-Pro-AMC peptide (BACHEM, #L-1215) in a DDP9 assay buffer (50 mM HEPES, pH 8) for 30 min at 37° C. in 96-well black plates (Nunc, #237108). To assay rhDPP9 activity inhibition by test compounds, test compounds were pre-incubated with the enzyme for 15 min at 37° C. before starting the reaction by substrate addition in 96-well black plates (Nunc, #237108). 7-Amino-4-Methylcoumarin (AMC) release was detected by measuring fluorescence at Ex/Em 380/460 nm using a Multifunction Microplate Reader (Synergy 4, Biotek). All measurements were carried out in triplicate. Val-boroPro, a non-specific prolyl peptidase inhibitor, was used as a positive control.