Table 1. Reaction conditions for measurement of DPP-2, DPP-8, DPP-9, PEP, and FAPα activities.

Enzymes	DPP-2	DPP-8	DPP-9	PEP	FAPα
Assay buffer*	100 mmol/L DMGA buffer(pH 5.5)	100 mmol/L Tris-HCl buffer(pH 7.5)	100 mmol/L Tris-HCl buffer(pH 7.5)	25 mmol/L glycine,25 mmol/L acetic acid, 23 mmol/LMES,75 mmol/L Tris, and100 mmol/L NaCl(pH 8.0)	88 mmol/L Na-K phosphate buffer(pH 7.0)
Substrates*	0.5 mmol/L Lys-Ala-pNA	1 mmol/L Gly-Pro-pNA	2 mmol/L Gly-Pro-pNA	2 mmol/L Ala-Pro-pNA	0.5 mmol/L Suc-Ala-Pro-pNA
Trelagliptin *	0.03, 0.1, 0.3, 1, 3, 10, 30 and 100 μmol/L
Temperature and duration	37°C, 60 min	37°C, 90 min	37°C, 90 min	37°C, 60 min	37°C, 60 min

*Final concentrations are listed.