Streptavidin and neutralite avidin are tetrameric biotin-binding proteins containing four identical subunits each of which can bind to biotin with a high degree of specificity and affinity. The Avidin-Biotin Complex is the strongest known non-covalent interaction (Kd ~10-15) between a protein and ligand.
Streptavidin was originally isolated from the culture broth of the bacterium Streptomyces avidinii. SouthernBiotech streptavidin products use a recombinant form of streptavidin that can be utilized for the coating of solid phases (e.g., beads, microplates) as well as with biotin-labeled antibodies in immunological detection systems. Avidin is purified from egg whites with neutralite avidin being a deglycosylated form of native avidin. The removal of the glycosylation leads to reduced non-specific binding and a more neutral isoelectric point. Both streptavidin and neutralite avidin provide exceptional performance in western blot, ELISA, flow cytometry, and immunohistochemical applications requiring biotin-binding proteins for detection.