L49-sFv-bL

L49-sFv-bL is a **recombinant fusion protein** consisting of the single-chain variable fragment (sFv) of the L49 monoclonal antibody, covalently linked to the enzyme β-lactamase. The L49 antibody fragment binds to the human p97 melanoma-associated antigen, allowing for selective localization to tumor cells expressing p97. The β-lactamase component serves as an enzyme that can activate specific prodrugs (such as cephalosporin-based anticancer prodrugs) by hydrolyzing the β-lactam ring, thereby converting the inactive prodrug into a cytotoxic agent at the tumor site. This provides a targeted anti-tumor strategy as a component of "Antibody-Directed Enzyme Prodrug Therapy" (ADEPT), aimed at increasing the selective toxicity to tumors while sparing normal tissues. L49-sFv-bL has been studied in preclinical settings, particularly for the treatment of melanoma, and is designed for intravenous administration[1][3][5].