m-PEG3-succinimidyl carbonate is a PEG-based PROTAC linker 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]. Miller MA, et al. Amphiphilic conjugates of human brain natriuretic peptide designed for oral delivery: in vitro activity screening. Bioconjug Chem. 2006 Mar-Apr;17(2):267-74.