DBCO-Dap(m-PEG4)-Val-Cit-PAB(m-PEG8)-MMAE cyclopropene 215 SMILES CC(C)(C)OC(=O)CN1CCN(CC(=O)NCCOCCOCCOCCOCCOCCNC(=O)CCN2C(=O)C=CC2=O)CCN(CC(=O)OC(C)(C)C)CCN(CC(=O)OC(C)(C)C)CC1 Purity (HPLC)

215 SMILES CC(C)(C)OC(=O)CN1CCN(CC(=O)NCCOCCOCCOCCOCCOCCNC(=O)CCN2C(=O)C=CC2=O)CCN(CC(=O)OC(C)(C)C)CCN(CC(=O)OC(C)(C)C)CC1 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

or dibenzocyclooctyne

366 Purity (HPLC) >= 95% Solubility DMSO

031 SMILES CC(C)(C)OC(=O)CN1CCN(CC(=O)NCCCCCNC(=O)CCN2C(=O)C=CC2=O)CCN(CC(=O)OC(C)(C)C)CCN(CC(=O)OC(C)(C)C)CC1 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

715 SMILES OC(=O)CN1CCN(CC(O)=O)CCN(CC(=O)NCCOCCOCCOCCOCCN=[N+]=[N-])CCN(CC(O)=O)CC1 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

DBCO-Dap(m-PEG4)-Val-Cit-PAB(m-PEG8)-MMAE cyclopropene 215 SMILES CC(C)(C)OC(=O)CN1CCN(CC(=O)NCCOCCOCCOCCOCCOCCNC(=O)CCN2C(=O)C=CC2=O)CCN(CC(=O)OC(C)(C)C)CCN(CC(=O)OC(C)(C)C)CC1 Purity (HPLC)SOLU KNEX cleavable linker features a Val Cit dipeptide. In this product, a DBCO Dap(m PEG4) moiety replaces the conventional maleimidocaproyl (MC) unit to enhance aqueous solubility. DBCO is a strained alkyne commonly used in copper free click chemistry, specifically in the strain promoted azide alkyne cycloaddition (SPAAC) reaction. Additionally, m PEG8 is attached to the commonly used self immolative para aminobenzyl (PAB) moiety to further