N-(Azido-PEG4)-biocytin（Cat No.:I014504）is a multifunctional biotinylation reagent that combines a biotin moiety for strong streptavidin/avidin binding with an azide group for bioorthogonal click chemistry. The PEG4 spacer enhances hydrophilicity, flexibility, and reduces steric hindrance, ensuring efficient solubility and accessibility in both aqueous and organic systems. The biocytin core provides robust biotin functionality with additional structural features for versatile conjugation. This reagent is widely employed in proteomics, chemical biology, imaging, and drug discovery, enabling site-specific labeling, affinity capture, and enrichment of biomolecules in complex biological environments.