Ald-CH2-PEG5-azide is a non-cleavable linker consisting of a five unit PEG chain, commonly employed in the synthesis of antibody-drug conjugates (ADCs)[1].
Amino-PEG4-alcohol is a PEG-based PROTAC linker that can be employed for the synthesis of PROTACs[1]. It is also a non-cleavable 4 unit PEG ADC linker utilized in the synthesis of antibody-drug conjugates (ADCs)[2].