EphB4-IN-2

EphB4-IN-2 (compound 66) is a tyrosine kinase inhibitor with an IC50 value of 1.6 nM for human EphB4 and shows selectivity towards kinases with a threonine gatekeeper residue. EphB4-IN-2 also exhibits high ligand efficiency.

EphB4-IN-2 (compound 66) acts as a potent inhibitor of recombinant EphB4 kinase activity in a FRET-based enzymatic assay, with an IC50 of 5 nM, at concentrations ranging from 10 pM to 20 μM over 2 hours. In a [γ-33P]ATP-based enzymatic assay, EphB4-IN-2 (110 pM-10 μM; 30 minutes) inhibits recombinant EphB4 kinase activity with an IC50 of 1.6 nM. It efficiently inhibits 9 out of 10 tested recombinant Eph receptor kinases with low nanomolar IC50 values (1.1-15 nM) but shows significantly reduced activity against EphA7 with an IC50 of 1118 nM. Additionally, EphB4-IN-2 (1 μM; 30 minutes) strongly inhibits recombinant EphA2, EphB3, Src, Lck, and Yes1 kinases, exhibits moderate activity against CSK, BTK, and HER-4, and shows very low activity against most other tested kinases. EphB4-IN-2 (1 μM) binds with high affinity to 15 kinases with a small gatekeeper residue among 49 tested recombinant kinases, predominantly from the Eph, Src, and Abl families.