Streptavidin (MW ~66kD) binds specifically with biotin (244D). It is derived from the bacterium Streptomyces avidinii and bears a remarkable similarity to chicken egg-white avidin both in three-dimensional structure and its ability to bind biotin with extremely high affinity (Kd=10e-15M). It is a tetrameric protein capable of binding up to 4 biotin molecules. Unlike avidin, Streptavidin is non-glycosylated and is essentially neutral in charge, whereas avidin (pH 10.5) is basic at neutral pH. Because of this, streptavidin has considerably less non-specific binding resulting in less background. It has replaced avidin as the reagent of choice for most applications where protein interactions may cause background. Streptavidin (Streptomyces avidinii), a biotin binding protein with exceptionally strong binding affinity, is covalently coupled to Sepharose 4B Streptavidin Sepharose: The same high performance streptavidin media used in Streptavidin columns for fast, reliable purification of biotinylated compounds. Ideal for packing into columns when larger scale purifications are required. Extremely useful for exploiting either the strong interactions of biotin and streptavidin or the somewhat weaker interactions of 2-iminobiotin and streptavidin. The base matrix is a rigid, highly cross-linked beaded agarose with high chemical stability. The immobilized streptavidin binds biotin and biotinylated substances and can be used for affinity chromatography applications. The interaction between streptavidin and biotin is very strong and requires denaturating conditions for elution, which may destroy both the ligand and the sample. Alternatively, it can be used in the purification of antigens, where biotinylated antibodies are incubated with antigen. The biotinylated antibody-antigen complex binds to Streptavidin Sepharose from which the antigen can be eluted. Another example is to utilise the interaction between 2-iminobiotin and streptavidin, eluting the bound substances at pH 4. Matrix: Agarose beads, 4% Ligand Density: 2mg/ml Particle Size: 53-180um Binding Capacity: 6mg biotinylated BSA or 300nmol biotin/ml gel Exclusion Limit: ~2x10e7 pH Stability (Storage): 3-10 Binding Buffer: 20mM sodium phosphate, 0.15M sodium chloride, pH 7.5 Elution Buffer: 8M guanidineHCl, pH 1.5 Applications: Suitable for use in affinity chromatography. Other applications not tested. Storage and Stability: Store in 0.01M sodium phosphate, 0.15M sodium chloride, pH 7.2, 0.05% sodium azide. May be stored at 4C. Do not freeze. Stable for 6 months after receipt.
Form:
Supplied as a 50% slurry of 1X sodium chloride, 0.02% sodium azide.
CAS Number:
[9013-20-1]
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