Streptavidin-ZAP

a chemical conjugate of streptavidin and the ribosome-inactivating protein, saporin

Streptavidin is isolated from Streptomyces avidinii and has a molecular weight of 53 kDa in its recombinant form. The streptavidin in Streptavidin-ZAP has no carbohydrate group and a neutral isoelectric point, therefore reducing nonspecific binding levels as compared to avidin. Streptavidin is less water soluble than avidin. Streptavidin is also a tetrameric protein, with each subunit able to bind a single biotin molecule. Biotin, a 244 dalton vitamin found in tissue and blood, binds with high affinity to streptavidin. In fact, the streptavidin-biotin interaction is the strongest known noncovalent biological interaction (Ka = 10¹⁵ M^-1) between protein and ligand. The bond formation between streptavidin and biotin is rapid and essentially non-reversible, unaffected by most extremes of pH, organic solvents, and denaturing reagents. Extensive chemical modification has little effect on the activity of the protein. The streptavidin-biotin interaction has found extensive use as a research tool. A variety of molecules, including lectins, proteins, and antibodies, can be biotinylated and reacted with streptavidin labeled probes or other detection reagents for use in biological assays.

Streptavidin-ZAP “piggybacks” onto YOUR biotinylated material in order to evaluate the ability of the reagent to internalize upon binding to its receptor. Once the conjugate is internalized, saporin breaks away from the targeting agent and inactivates the ribosomes, which causes protein inhibition and, ultimately, cell death. Potency may vary according to the specificity and affinity of YOUR material to ITS receptor. When your in vitro results confirm the desired specificity, it is recommended that you order a custom conjugation of your material directly to saporin.

Elimination of Specific Cell Type

• Cells targeted by biotinylated materials will be eliminated with this reagent.
• Potency may vary according to the specificity and affinity of YOUR material to ITS receptor.
• ATS recommends that you order a custom conjugation of your material directly to saporin when the in vitro results confirm the desired specificity.

Effective Tool

• Biotinylation of antibodies is a commonly used technique. Advanced Targeting Systems offers a biotinylation service for a variety of molecules, including lectins, proteins, and antibodies.
• Using streptavidin-ZAP and biotinylated targeting agents, specific cytotoxins can be created JUST BY MIXING!
• Apply your new biotin-streptavidin targeted toxin to eliminate target cells.

Protocols: Preparing for a Cytotoxicity Assay

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Check out these articles in Targeting Trends for more information:

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