JTT 551 shows low affinity at CD45 PTP (CD45) and leucocyte common antigen-related (LAR) PTP with Kis of both >30 μM. Furthermore, JTT-551 (10 and 30 μM) enhances the insulin-induced deoxyglucose uptake in a dosedependent manner.JTT 551 is selective a protein tyrosine phosphatase 1B (PTP1B) inhibitor, with Kis of 0.22 μM and 9.3 μM for PTP1B and TCPTP (T-cell protein tyrosine phosphatase), respectively.

JTT 551 also significantly reduces triglyceride (TG) level at 30 mg/kg on Day 7 but does not alter insulin and total cholesterol (TC) levels.JTT 551 (3 mg/kg, 30 mg/kg, p.o.) dose-dependently decreases blood glucose level on Days 7, 14 and 28 in db/db Mice.