Streptavidin (CAS 9013-20-1)

Streptavidin is a tetrameric protein secreted by Streptomyces avidinii which binds firmly to biotin (sc-204706). Streptavidin is wilyde used in molecular biology through its unique high affinity for the vitamin biotin. The dissociation constant (Kd) of the biotin-streptavidin complex is about ~10-15 mol/L. The strong affinity recognition of biotin and biotinylated molecules has made streptavidin one of the most important components in diagnostics and laboratory kits. The streptavidin/biotin system has one of the biggest free energies of association of yet observed for noncovalent binding of a protein and small ligand in aqueous solution (K_assoc = 10**14). The complexes are also extremely stable over a wide range of temperature and pH. The Streptavidin preparation contains an N- and C-terminal shortened variant (core streptavidin) with improved properties concerning homogeneity, solubility, resistance towards proteolytic degradation and accessibility of the biotin binding pocket as compared to native streptavidin. Streptavidin has a molecular weight of 55kDa.

Specific Activity: Greater than 15.7 U/mg, 1 unit binds 1µg biotin. Proteolytic Activity: Less than 10-3 U/mg protein (Azocoll, 25°C, 24 h, pH 8.0). Streptavidin is considered stable at 4°C for up to 3 weeks; for long term storage, desiccate below -18°C.

SDS

Related Product Categories