Used in bioconjugation for click chemistry applications, particularly in labeling and detecting biomolecules. The alkyne group reacts with azide-containing compounds via copper-catalyzed azide-alkyne cycloaddition (CuAAC), enabling efficient and selective attachment to proteins, nucleic acids, or cell surfaces. The PEG3 spacer enhances solubility and reduces steric hindrance, improving reaction efficiency. Biotin allows subsequent detection or purification using streptavidin-based systems, making this reagent valuable in proteomics, imaging, and diagnostic assays.