Azido-PEG6-NHS ester is a cleavable 6 unit PEG ADC linker used in the synthesis of antibody-drug conjugates (ADCs)[1]. Azido-PEG6-NHS ester is also a PEG- and Alkyl/ether based PROTAC linker that can be used in the synthesis of PROTACs[2].
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].
References:
[1]. Thiele NA, et al. An Eighteen-Membered Macrocyclic Ligand for Actinium-225 Targeted Alpha Therapy. Angew Chem Int Ed Engl. 2017 Nov 13;56(46):14712-14717.
[2]. John W. Babich, et al. Trifunctional constructs with tunable pharmacokinetics useful in imaging and anti-tumor therapies. WO2018187631A1.