Bis-PEG6-NHS ester

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.
ADCs are comprised of an antibody to which is attached an ADC cytotoxin through an ADC linker.