Azide-Dap(m-PEG4)-Val-Ala-PAB(m-PEG4)-Exatecan

SOLU-KNEX® cleavable linker features a Val-Ala dipeptide. In this product, a Azide-Dap(m-PEG4) moiety replaces the conventional maleimidocaproyl (MC) unit to enhance aqueous solubility. The azide functional group is widely utilized in bioconjugation via click chemistry to enable efficient and selective attachment of biomolecules. Additionally, m-PEG4 is attached to the commonly used self-immolative para-aminobenzyl (PAB) moiety to further increase aqueous solubility. The payload is Exatecan, a highly potent topoisomerase I inhibitor derived from camptothecin, which induces DNA damage by stabilizing the topoisomerase I–DNA complex, resulting in cell-cycle arrest and apoptosis. Derived from established ADC linker architectures, SOLU-KNEX® ADC linkers integrate solubilizing moieties—such as PEG, amine-containing groups, or polysarcosine (PSAR), to enhance aqueous solubility. Solubility and physicochemical properties can be finely tuned through selection and combination of these gro