Streptavidin (Streptomyces avidinii), CAS [[9013-20-1]]

Produktübersicht

• Artikelname: Streptavidin (Streptomyces avidinii), CAS [[9013-20-1]]
• Artikelnummer: USB-209209
• Hersteller Artikelnummer: 209209
• Alternativnummer: USB-209209-1
• Hersteller: US Biological
• Kategorie: Molekularbiologie

Produktbeschreibung

Streptavidin is a 53kD tetrameric protein purified from the bacterium Streptomyces avidinii. It finds wide uses in immunoassay and molecular biology due to its extraordinarily strong affinity for the vitamin biotin, the dissociation constant (Kd) of the biotin-streptavidin complex is on the order of ~10-15mol/L, ranking among one of the strongest known non-covalent interactions. There are considerable differences in the composition of avidin (found in egg white) and streptavidin, but they are remarkably similar in other respects. Both proteins form tetrameric complexes to function in which each subunit can bind one molecule of biotin. Streptavidin is much less soluble in water than avidin, and it lacks avidins extensive glycosylation. Streptavidin has a mildly acidic isoelectric point (pI) of ~5. Because streptavidin lacks any carbohydrate modification and has a near-neutral pI, it has the advantage of much lower nonspecific binding than avidin. Deglycosylated avidin is more comparable to the size, pI and nonspecific binding of streptavidin. Streptavidins affinity for biotin is exploited in wide ranging biochemical assays, including western blot, ELISA, ELISPOT and pull-down assays. Streptavidin immobilized onto solid supports (ELISA plates, agarose, nitrocellulose etc) is also used as purification media to capture biotin-labelled protein or nucleic acid molecules. For example, cell surface proteins can be specifically labelled with membrane impermeable biotin reagent, then specifically captured using an avidin-based support. The 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. Source: Streptavidin, from S. avidinii by purification from fermentation broth Proteolytic Activity: ~10-3U/mg protein (Azocoll, 25C, 24h, pH 8.0). Endotoxin: ~0.1ng/ug (IEU/ug) Binding Capacity Determnined to be ~15-20units/mg. Unit Definition: One unit is defined as the amount of protein which binds 1ug of biotin (Green NM et al (1963) Biochem. J. 89, 599) Storage and Stability: May be stored at 4C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.

Produkteigenschaften

• Reinheit: Highly Purified (~95%)
• Formulierung: Supplied as a powder from 10mM potassium phosphate, pH 6.5. No preservative added. Reconstitute with sterile dH2O
• CAS Nummer: [9013-20-1]