Used in bioconjugation and bioorthogonal chemistry for labeling and modifying biomolecules. Its azide group enables click chemistry reactions, particularly copper-catalyzed azide-alkyne cycloaddition (CuAAC), allowing efficient attachment to alkyne-functionalized compounds. The PEG3 spacer enhances solubility and provides flexibility, improving accessibility and reducing steric hindrance during conjugation. The aminoxyacetamide moiety can react selectively with carbonyl groups, such as those in ketones or aldehydes, forming stable oxime bonds. This dual functionality makes it valuable in probe development, protein modification, and the synthesis of antibody-drug conjugates or imaging agents. Commonly applied in chemical biology, drug delivery systems, and diagnostic assays where selective and controlled coupling is required.