Introduction Streptavidin is a tetrameric protein secreted by Streptomyces avidinii which binds firmly to biotin. Streptavidin is widely 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.
Description Streptavidin Streptomyces Avidinii Recombinant produced in E.Coli.
The molecular weight per tetramer is approximately 53kDa.
Extinction coefficient per subunit: 41326 M-1 cm-1.
Source Escherichia Coli.
Physical Appearance Sterile Filtered White lyophilized (freeze-dried) powder.
Formulation Lyophilized in 10mM potassium phosphate buffer pH 6.5.
Solubility It is recommended to reconstitute the lyophilized Streptavidin in sterile 18MΩ-cm H2O not less than 100µg/ml, which can then be further diluted to other aqueous solutions.
Stability Streptavidin is shipped at ambient temperature, upon arrival store at -20°C.
Purity Greater than 95.0% as determined by SDS-PAGE.
Specific Activity > 17U/mg (one unit binds 1 μg D-biotin at pH 8.9).
Proteolytic Activity < 10-3 U/mg protein (Azocoll, 25 °C, 24 h, pH 8.0).
Usage CHI's products are furnished for LABORATORY RESEARCH USE ONLY. The product may not be used as drugs, agricultural or pesticidal products, food additives or household chemicals.