LSKL, Inhibitor of Thrombospondin (TSP-1) (TFA)

• CAT Number: I045978
• CAS Number: 2828433-17-4
• Molecular Formula: C23H43F3N6O7
• Molecular Weight: 572.62
• Purity: ≥95%
• Synonyms: (2S)-6-amino-N-[(2S)-1-amino-4-methyl-1-oxopentan-2-yl]-2-[[(2S)-2-[[(2S)-2-amino-4-methylpentanoyl]amino]-3-hydroxypropanoyl]amino]hexanamide;2,2,2-trifluoroacetic acid
• InChI: InChI=1S/C21H42N6O5.C2HF3O2/c1-12(2)9-14(23)19(30)27-17(11-28)21(32)25-15(7-5-6-8-22)20(31)26-16(18(24)29)10-13(3)4;3-2(4,5)1(6)7/h12-17,28H,5-11,22-23H2,1-4H3,(H2,24,29)(H,25,32)(H,26,31)(H,27,30);(H,6,7)/t14-,15-,16-,17-;/m0./s1
• InChIKey: FULCVSARTMWAGA-SITLLQIKSA-N
• SMILES: CC(C)CC(C(=O)NC(CO)C(=O)NC(CCCCN)C(=O)NC(CC(C)C)C(=O)N)N.C(=O)(C(F)(F)F)O

LSKL (CAT: I045978 is a synthetic tetrapeptide (Leu-Ser-Lys-Leu) that acts as a potent inhibitor of thrombospondin-1 (TSP-1). By blocking the interaction between TSP-1 and latent transforming growth factor-β1 (TGF-β1), LSKL prevents TSP-1–mediated activation of TGF-β signaling. This inhibition makes LSKL a valuable tool for studying fibrosis, tissue remodeling, and tumor progression, where aberrant TGF-β activation plays a central role. Supplied as a trifluoroacetate (TFA) salt for enhanced stability, LSKL is widely used in cardiovascular, renal, hepatic, and oncology research to investigate TSP-1/TGF-β–related pathways and their potential as therapeutic targets in fibrotic and proliferative diseases.