Purified, conjugated and activated streptavidin for biotin-binding methods.
Thermo Scientific Pierce Streptavidin and Conjugates include streptavidin in a purified form, conjugated to enzymes or fluorophores or activated for crosslinking to sulfhydryl or carbonyl groups.
These purified and conjugated forms of recombinant streptavidin protein enable detection of biotinylated antibodies and other probes in a variety of standard assay methods, including Western blotting, ELISA, immunohistochemistry and fluorescence imaging. Purified streptavidin and the streptavidin-HRP conjugates (peroxidase-conjugated streptavidin) are supplied lyophilized in phosphate-based buffers for immediate reconstitution with water. Alkaline Phosphatase conjugates are supplied as a liquid in a Tris-based buffer.
Recombinant streptavidin – high-quality protein, 53kDa, pI = 6.8 to 7.5
Pure protein and enzyme conjugates – choose pure, unconjugated protein for biotin blocking and controls; enzyme conjugates for substrate-based detection
Fluorophore conjugates – standard fluorescent forms (fluorescein, rhodamine, etc.) for traditional immunofluorescence techniques
Activated preparations – choose a maleimide-activated or hydrazide-activated form to prepare a custom streptavidin conjugate with sulfhydryl- or carbohydrate-containing molecule
Streptavidin is biotin-binding protein that was originally isolated from Streptomyces avidinii. In contrast to avidin, streptavidin has no carbohydrate and has a mildly acidic pI of 5. Thermo Scientific Pierce Streptavidin products use a recombinant form of streptavidin having a mass of 53,000 daltons and a near-neutral pI. Streptavidin is a tetrameric protein, with each subunit binding one molecule of biotin with affinity similar to that of avidin. Guanidinium chloride will dissociate avidin and streptavidin into subunits, but streptavidin is more resistant to dissociation.
Applications for enzyme-labeled (HRP, AP) streptavidin:
Enzyme immunoassays (EIA), including enzyme-linked immunsorbent assays (ELISA) with biotinylated antibodies
Cell and tissue staining (for light microscopy)
Western blotting (WB) and other membrane-based biotin detection