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.
Streptavidin is a tetrameric protein secreted by Streptomyces avidinii which binds firmly to biotin. Streptavidin is wilyde used in molecular biology throµgh 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.
Bacterium Streptomyces avidinii.
Sterile Filtered lyophilized powder.
Lyophilized (1mg/ml) in 50mM NaCl, pH 9.0.
Gives a clear solution at 5mg/ml in 0.1M NaCl.
Streptavidin althoµgh stable at 4°C for 3 weeks, should be stored desiccated below -18°C. For longer storage in dissolved form add 1mM EDTA and/or 0.02 % NaN3 or pass the solution throµgh a sterile filter.Please prevent freeze-thaw cycles.
Greater than 95.0% as determined by SDS-PAGE.
NeoScientific's products are furnished for LABORATORY RESEARCH USE ONLY. The product may not be used as drµgs, agricultural or pesticidal products, food additives or household chemicals.
Streptavidin may be used to visualize biotin conjµgated molecules in ELISA, blotting and histological technique.