Triethylene glycol bis(p-toluenesulfonate) is a PEG-based PROTAC linker that can be used in the synthesis of PROTACs[1].
PROTACs contain two different ligands connected by a linker; one is a ligand for an E3 ubiquitin ligase and the other is for the target protein. PROTACs exploit the intracellular ubiquitin-proteasome system to selectively degrade target proteins[1].
[1]. Snaebjornsson MT, et al. Non-canonical functions of enzymes facilitate cross-talk between cell metabolic and regulatory pathways. Exp Mol Med. 2018 Apr 16;50(4):34.