Used in bioconjugation processes to link molecules with high specificity and stability. Commonly applied in the development of antibody-drug conjugates (ADCs) and peptide-protein conjugates. The PFP ester group reacts efficiently with primary amines, enabling labeling of biomolecules under mild conditions. The N3-PEG4-C2 spacer provides water solubility and reduces steric hindrance, improving reaction efficiency and biomolecule functionality. Often used in click chemistry workflows after azide introduction, allowing modular assembly of complex biological probes or drug candidates. Suitable for applications in diagnostics, targeted therapeutics, and chemical biology research.