MAP kinase is a serine/threonine kinase that is activated by MEK through a phosphorylation cascade. The cascade starts with extracellular signals transmitted by growth factor-regulated receptor tyrosine kinases or G-protein coupled receptors. Dually phosphorylated (Thr and Tyr) MAP kinase translocates from the cytoplasm to the nucleus, where it phosphorylates protein transcription factors, transducing extracellular signals into genomic responses, proliferation or differentiation.

One unit of activated MAP kinase will transfer 1 nmol of phosphate from ATP to myelin basic protein per min at 30 °C.

Lyophilized powder containing Tris, pH 7.5, NaCl, and EGTA, with DTT and trehalose as stabilizers