Azido-PEG1-Val-Cit-PAB-OH is a cleavable ADC linker. The Val-Cit will specifically be cleaved by Cathepsin B. As this enzyme is only present in the lysosome, the ADC payload will be released only in the cell. Azido group will react with DBCO, BCN or other Alkyne group through click chemistry, PEG spacer increases aqueous solubility.
