MK-1775 is a potent and selective inhibitor of the tyrosine kinase WEE1 (IC50 = 5.2 nM). It selectively targets and inhibits WEE1, a tyrosine kinase that phosphorylates cyclin-dependent kinase 1 (CDC2) to inactivate the CDC2/cyclin B complex. Inhibition of WEE1 activity prevents the phosphorylation of CDC2 and impairs the G2 DNA damage checkpoint. This may lead to apoptosis upon treatment with DNA damaging chemotherapeutic agents. MW: 500.6. Purity ≥98% by HPLC