DBCO-Hexanoyl-Gly-Gly-Phe-Gly-PAB(m-PEG8)-PNP Size:25mg NCCCCC(NS(=O)(=O)C1=CC=C(C(=C1)S([O-])(=O)=O)C1=C2C=C3CCC[N+]4=C3C(CCC4)=C2OC2=C3CCCN4CCCC(C=C12)=C34)C(O)=O Purity (HPLC): ≥ 95%

NCCCCC(NS(=O)(=O)C1=CC=C(C(=C1)S([O-])(=O)=O)C1=C2C=C3CCC[N+]4=C3C(CCC4)=C2OC2=C3CCCN4CCCC(C=C12)=C34)C(O)=O Purity (HPLC): ≥ 95% Shipping Conditions: room temperature Storage Conditions: Refrigerated Regulatory Statement: For Research Use Only

91 SMILES CC1=C(SC=N1)C1=CC=C(CNC(=O)[C@@H]2C[C@@H](O)CN2C(=O)[C@@H](NC(=O)CCOCCOCCOCCOCCOCCN=[N+]=[N-])C(C)(C)C)C=C1 Purity (HPLC) >= 95% Shipping Conditions Room temperature Storage Conditions Refrigerated Shelf Life 12 months after the date of delivery Regulatory Statement For Research Use Only

84 SMILES CC1=C(SC=N1)C1=CC=C(CNC(=O)[C@@H]2C[C@@H](O)CN2C(=O)[C@@H](NC(=O)CCOCCOCCOCCOCC#C)C(C)(C)C)C=C1 Purity (HPLC) >= 95% Shipping Conditions Room temperature Storage Conditions Refrigerated Shelf Life 12 months after the date of delivery Regulatory Statement For Research Use Only

a highly potent topoisomerase I inhibitor derived from camptothecin

Abdul-Hadi

DBCO-Hexanoyl-Gly-Gly-Phe-Gly-PAB(m-PEG8)-PNP Size:25mg NCCCCC(NS(=O)(=O)C1=CC=C(C(=C1)S([O-])(=O)=O)C1=C2C=C3CCC[N+]4=C3C(CCC4)=C2OC2=C3CCCN4CCCC(C=C12)=C34)C(O)=O Purity (HPLC): ≥ 95%SOLU KNEX cleavable linker features a Gly Gly Phe Gly (GGFG) peptide. m PEG8 is attached to the commonly used self immolative para aminobenzyl (PAB) moiety to increase aqueous solubility. The PNP (para nitrophenyl) moiety serves as an activating leaving group, enabling efficient and selective conjugation of the payload to the linker. Derived from established ADC linker architectures, SOLU KNEX ADC linkers integrate solubilizing moietiessuch as PEG,