IC50: 0.48 nM (DPPII); Ki: 0.082 nM (DPPII)

UAMC00039 has an IC ₅₀ of 0.48±0.04 nM and a high selectivity for DPPII compared to DPPIV (IC ₅₀ =165±9 μM) and DPP activity not caused by DPPII or DPPIV. UAMC00039 seems a promising tool to unravel the function of DPPII as well as to validate its potential as a therapeutic target. The efficacy of a DPPII inhibitor in cell culture depends not only on the inhibitors’ potency towards the enzyme but also on its stability in the medium and its ability to enter the cell. UAMC00039 is stable for at least 48 h at 37 °C in culture medium and in DPPII assay buffer. The compound is able to enter PBMC within 1 min resulting in a concentration-dependent inhibition of intracellular DPPII activity without affecting the ‘non-DPPII’ DPP activity. 1 and 100 μM UAMC00039 inhibits DPPII activity of PBMC and U937 cells more than 90%.

A dose dependent inhibition of DPPII but not of DPPIV is observed in the peripheral organs of both the rats and the mice (after oral administration) and the rabbits (after IV administration). UAMC00039 tested orally at 2 mg/kg does not cause signs of acute toxicity and does not cause any significant changes in the following functions that are evaluated: general behaviour, body temperature, respiration, bleeding time, blood pressure, urine volume, liver function, fasting glucose and gastrointestinal parameters like acidity, motility and irritation.