SPDP-PEG4-acid

• CAT Number: I016477
• CAS Number: 581065-97-6
• Molecular Formula: C19H30N2O7S2
• Molecular Weight: 462.58
• Purity: ≥95%
• Synonyms: 3-[2-[2-[2-[2-[3-(pyridin-2-yldisulfanyl)propanoylamino]ethoxy]ethoxy]ethoxy]ethoxy]propanoic acid
• InChI: InChI=1S/C19H30N2O7S2/c22-17(5-16-29-30-18-3-1-2-6-21-18)20-7-9-26-11-13-28-15-14-27-12-10-25-8-4-19(23)24/h1-3,6H,4-5,7-16H2,(H,20,22)(H,23,24)
• InChIKey: IJDPYTZOKIVWAN-UHFFFAOYSA-N
• SMILES: C1=CC=NC(=C1)SSCCC(=O)NCCOCCOCCOCCOCCC(=O)O

SPDP-PEG4-acid(CAT: I016477) is a heterobifunctional PEG linker that combines a succinimidyl 3-(2-pyridyldithio)propionate (SPDP) group with a terminal carboxylic acid. The SPDP moiety enables thiol-reactive disulfide exchange, allowing stable yet cleavable conjugation to cysteine residues or sulfhydryl-containing molecules. The PEG4 spacer improves aqueous solubility, adds flexibility, and reduces steric hindrance during coupling. The terminal carboxylic acid can be further activated for amide bond formation with amines, expanding its utility in bioconjugation. SPDP-PEG4-acid is widely used in protein modification, antibody–drug conjugates, and chemical biology research, offering a versatile tool for designing cleavable and functionalized biomolecular linkers.