Used in antibody-drug conjugates (ADCs) as a cleavable linker-payload system. The valine-citrulline (VC) dipeptide enables selective release of the drug in the presence of cathepsin B, an enzyme overexpressed in tumor cells. The PAB (para-aminobenzylcarbamate) spacer facilitates efficient drug release upon cleavage. DMEA (dimethyl ethanolamine) acts as the cytotoxic payload, inducing cell death by disrupting cellular functions. The Mal-PEG4 component allows site-specific conjugation to thiol groups on antibodies, enhancing stability and pharmacokinetics. This construct improves therapeutic index by minimizing off-target toxicity and maximizing tumor-specific drug delivery.