Streptavidin

Streptavidin is a bacterial protein (from Streptomyces avidinii) that has an exceptionally high binding affinity for biotin (B7) . Streptavidin-biotin binding is one of the strongest known non-covalent interactions and is highly resistant to many conditions that would typically cause dissociation (such as organic solvents, denaturants, detergents, and extreme temperatures or pH) . Streptavidin's affinity for biotin can be employed in a variety of experimental uses, from purifications to standards, to means of detection or pull down experiments. Streptavidin has been tested by SDS-PAGE and is suitable for use as antigen, as a control or standard in assays, and most other immunological methods as well as enzyme conjugates and complexes; Southern blots and other methodologies related to DNA and RNA analysis; Western blots; and purification of proteins or other antigens with biotinylated antibodies or lectins by use of immobilized streptavidin.