Used in antibody-drug conjugates (ADCs) as a cleavable linker-payload system. The linker is designed to be stable in circulation but releases the potent cytotoxic agent MMAE upon internalization into target cells, typically cancer cells. The OH-Glu-Val-Cit-PAB segment acts as a dipeptide-based linker that is selectively cleaved by cathepsin B, an enzyme overexpressed in many tumor tissues. This enables targeted delivery of MMAE, which disrupts microtubule assembly, leading to cell cycle arrest and apoptosis. This system enhances the therapeutic index of monoclonal antibodies by minimizing off-target toxicity while maximizing antitumor efficacy. Commonly employed in the development of anticancer biopharmaceuticals.