Streptavidin (CAS 9013-20-1)

Streptavidin is a tetrameric protein derived from the bacterium *Streptomyces avidinii*. It is renowned for its extraordinarily strong affinity for biotin, a vitamin that can be covalently attached to various biomolecules for biochemical applications. This biotin-streptavidin interaction, which is one of the strongest known non-covalent interactions (with a dissociation constant of 10^-15 M), is leveraged in a wide array of biochemical assays and research methodologies. Streptavidin′s mechanism of action revolves around its ability to bind biotinylated compounds, such as proteins, nucleic acids, and other molecules, which can then be isolated, detected, or quantified through various methods. This has made streptavidin integral to technologies like Western blotting, ELISA (Enzyme-Linked Immunosorbent Assay), and molecular imaging, where it is used to capture or visualize biotin-labeled targets. Furthermore, in the field of nanotechnology, streptavidin is used to organize biotin-tagged molecules on surfaces and in the construction of nanoscale assemblies. Its application extends to the purification of biomolecules, where streptavidin-coated beads or columns capture biotin-tagged proteins or nucleic acids from complex samples, facilitating a high degree of purification and recovery of the target substances. The robustness of the streptavidin-biotin interaction continues to make it an indispensable tool in research, underpinning many experimental designs that require precise and strong binding to carry out complex biochemical analyses.