Ac-PpYLKTK-OH White lyophilized solid. Supplied as a trifluoroacetate salt. HYGROSCOPIC. PACKAGED UNDER INERT GAS. A Stat3-SH2 domain binding phosphopeptide that acts as a selective inhibitor of Stat3 (signal transducers and activators of transcription 3) signaling with a DB50 of 235 µM (concentration of peptide at which DNA-binding activity is inhibited by 50%). Significantly lowers the DNA-binding activity of Stat3 by forming an inactive Stat3:peptide complex and reduces the levels of active Stat3:Stat3 dimers that can bind DNA. Displays greater affinity for Stat3, and to a lesser extent Stat1, over Stat5. Purity: ≥95% by HPLC. Supplied as a trifluoroacetate salt. Ac-Pro-Tyr(PO3H2)-Leu-Lys-Thr-Lys-OH Ref.: Turkson, J., et al. 2001. J. Biol. Chem. 276, 45443. | 
