STK11, a CAMK Ser/Thr protein kinase, has an essential role in G1 cell cycle arrest. STK11 phosphorylates and activates members of the AMPK-related subfamily of protein kinases. Defects in STK11 are a cause of predisposition to benign and maligant tumors including gastrointestinal and testicular cancers (Peutz-Jeghers syndrome).The synthetic peptide used to raise the antibody Cat. No. 200128 is selected from a sequence within the N-term region of human STK11. For blocking experiments, a 10 to 100 fold molar excess to antibody is recommended.