Iodo-PEG-Biotin is a bifunctional molecule that contains both an iodo group and a PEG linker attached to a biotin moiety. The iodo group allows for selective iodination of proteins or peptides, while the PEG linker increases solubility and reduces steric hindrance. Biotin, a vitamin H cofactor, binds with high affinity to streptavidin, making it useful for protein purification and detection. In pharmaceutical research and development, Iodo-PEG-Biotin is frequently used as a tool for site-specific protein labeling, conjugation of drugs to antibodies or other biomolecules, and for the development of targeted therapeutics. The unique properties of Iodo-PEG-Biotin make it a versatile reagent for a variety of applications in drug discovery and development.