Used in the development of antibody-drug conjugates (ADCs), this compound serves as a linker to connect cytotoxic drugs to antibodies. It enables targeted delivery of therapeutic agents to specific cells, minimizing damage to healthy tissues. The Val-Cit sequence is cleavable by cathepsin B, an enzyme found in lysosomes, ensuring controlled drug release. The PAB (para-aminobenzyl) group enhances stability in circulation, while the PEG2 spacer improves solubility and reduces aggregation. This makes it a critical component in cancer therapy, enhancing the efficacy and safety of ADCs.