U0126

Potent and selective non-competitive inhibitor of MAP kinase kinase(MEK). Inhibits MEK-1 and MEK-2 (IC₅₀ values of 0.07 and 0.06 µM respectively) with little or no effect on the activities of PKC, Abl, Raf, MEKK, ERK, JNK, MKK-3, MKK-4/SEK, MKK-6, Cdk2 or Cdk4.