Notes: Aminoethyl-SS-propionic acid is a cleavable disulfide linker.{66102,66103} It has been used in the synthesis of antibody-drug conjugates (ADCs) containing the antibody trastuzumab and a membrane-impermeable cytotoxin, which inhibits HER2 dimerization and induces cytotoxicity in HER2-positive breast cancer cells, respectively.{66103}