The Biotin moiety enables high-affinity binding to streptavidin or avidin, facilitating biomolecule purification, detection assays (e.g., ELISA), and imaging applications. Used in bioconjugation and bioorthogonal chemistry for labeling and detecting biomolecules in live cells. The azide group enables click chemistry reactions, such as copper-catalyzed azide-alkyne cycloaddition (CuAAC), allowing selective attachment to alkyne-modified biomolecules. The Dde group serves as an orthogonally protected primary amine handle that can be deprotected under mild conditions (e.g., with hydrazine), enabling sequential conjugation strategies without affecting other functional groups. TAMRA provides a red fluorescent tag for visualization via fluorescence microscopy or flow cytometry. The PEG4 and PEG3 spacers enhance water solubility, reduce nonspecific binding, and improve the flexibility and accessibility of the reactive groups. Commonly applied in proteomics, targeted imaging, development of diagnostic probes, and antibody-drug conjugates.