Biotin labelled Peptides

Biotin is a water-soluble B vitamin which is involved in a wide range of metabolic processes. Covalent addition of biotin to a protein, peptide, nucleic acid or other molecule is the process of biotinylation and once attached, biotin in turn binds with extremely high affinity and specificity to the proteins streptavidin and avidin. This binding is rapid, specific and is unlikely to disturb the natural function of the molecule due to the relatively small size of biotin. The streptavidin (and avidin)-biotin complex has very high stability towards solvents, denaturants, detergents, proteolytic enzymes, and extremes of temperature and pH allowing this interaction to be exploited in many areas of biochemistry.
Streptavidin is a tetramer and each subunit binds biotin with equal affinity. Multiple biotin molecules can be conjugated to a protein of interest, and this allows the binding of multiple streptavidin/avidin molecules which so increases the sensitivity of detection. A large number of biotinylation reagents exist that exploit the range of labelling methods. The purification of biotinylated proteins has been a widely used approach to identify protein-protein interactions and post-translational events in molecular biology.