Mal-Propionyl-PEG4-Gly-Gly-Phe-Gly-PAB(m-PEG4)-Exatecan clip [O-]C(=O)C1=CC(=CC=C1C1=C2C=C3CCC[N+]4=C3C(CCC4)=C2OC2=C3CCCN4CCCC(C=C12)=C34)C(=O)NCC#C Purity (HPLC): ≥ 95%

[O-]C(=O)C1=CC(=CC=C1C1=C2C=C3CCC[N+]4=C3C(CCC4)=C2OC2=C3CCCN4CCCC(C=C12)=C34)C(=O)NCC#C Purity (HPLC): ≥ 95% Shipping Conditions: room temperature Storage Conditions: Refrigerated Regulatory Statement: For Research Use Only

527 SMILES [N-]=[N+]=NCCOCCOCCOCCOCCNC1=C2C(=O)N(C3CCC(=O)NC3=O)C(=O)C2=CC=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

exhibited longer fluorescence lifetimes than its non-sulfonated counterparts

providing flexibility in protein labeling and tracking

349 SMILES OC(=O)CCCCOC1=C2C(=O)N(C3CCC(=O)NC3=O)C(=O)C2=CC=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

Mal-Propionyl-PEG4-Gly-Gly-Phe-Gly-PAB(m-PEG4)-Exatecan clip [O-]C(=O)C1=CC(=CC=C1C1=C2C=C3CCC[N+]4=C3C(CCC4)=C2OC2=C3CCCN4CCCC(C=C12)=C34)C(=O)NCC#C Purity (HPLC): ≥ 95%SOLU KNEX cleavable linker features a Gly Gly Phe Gly (GGFG) peptide. The conventional maleimidocaproyl (MC) unit is replaced by Mal Propionyl PEG4 moiety to enhance aqueous solubility. The Mal Propionyl group may also improve retro Michael addition stability during antibody conjugation. m PEG4 is attached to the commonly used self immolative para aminobenzyl (PAB) moiety to increase aqueous solubility. The payload is Exatecan, a highly potent