Streptavidin (Sepharose 4B)

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.\n\nStreptavidin Sepharose:\nThe 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.\n\nExtremely useful for exploiting either the strong interactions of biotin and streptavidin or the somewhat weaker interactions of 2-iminobiotin and streptavidin.\n\nThe 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.\n \nMatrix: \nHighly cross-linked agarose 6%\n\nAverage bead size:\n 34um \n\nBinding capacity: \n> 300nmol biotin/ml medium;\n6mg biotinylated BSA/ml medium \n\npH Stability: \n4-9 (long term), 2-10.5 (working) \n\nApplications:\nSuitable for use in Immunoprecipitation. Other applications have not been tested.\n\nRecommended Dilution:\n Immunoprecipitation: 50-100ul of 10% suspension for each sample. Upon boiling, may denature to show four subunits of ~15kD each.\nOptimal dilutions to be determined by the researcher.\n\nStorage and Stability:\nStore in 20% ethanol. May be stored at 4 degrees C. Do not freeze. Stable for at least 12 months. For maximum recovery of product, centrifuge the original vial prior to removing the cap.

Prices direct from United States Biological

Quick response times

Exclusive Biosave savings/discounts

SPECIFICATIONS

Catalog Number

S7973-89E

Size

1ml

Applications

IP

Form

Streptavidin Sepharose is supplied pre-swollen in 20% ethanol. Wash the required amount of medium with 10 volumes of binding buffer to remove the ethanol solution. Prepare a slurry with binding buffer in a ratio of 75% settled medium to 25% buffer.