Signal inhibition of TGF-beta 1 is often used for stem cell reprogramming and iPSC differentiation. Small kinase inhibitors are commonly used, but they lack specificity and may perturb other signaling pathways, causing cytotoxicity.

PG-002, a chemically-synthesized cyclic peptide with specific binding ability against TGF-beta 1 and lacks membrane-permeability, can specifically inhibit TGF-beta 1 signaling at extracellular conditions, making it a suitable replacement for small kinase inhibitors. The molecular weight of PG-002 is 2587.90 (acetate).