MC-Val-Cit-PABC-PNP, also known as Mc-Val-Cit-PABC-PNP, is a cathepsin cleavable ADC peptide linker. For example, FDA approved drug, brentuximab vedotin, adopts this linker. Protein- and peptide-drug conjugates hold a promising stance in the delivery of therapeutic agents by providing distinct advantage of improving therapeutic potential of drugs. Use of specialized linkers makes them unique in their in vivo therapeutic application by providing target tissue-specific release of drug.