Bis-PEG2-PFP ester is also a non-cleavable 2 unit PEG ADC linker used in the synthesis of antibody-drug conjugates (ADCs)^[1]. Bis-PEG2-PFP ester is also a PEG-based PROTAC linker that can be used in the synthesis of PROTACs^[2]. In Vitro: ADCs are comprised of an antibody to which is attached an ADC cytotoxin through an ADC linker^[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^[2].