Thermo Scientific MagnaBind Streptavidin Beads are convenient for affinity purification or separation methods involving of biotin-labeled molecules. To remove the MagnaBind Beads from the suspension, an external magnetic field is used.

Features of MagnaBind Streptavidin Beads:

• Composition: Silanized iron oxide
• Magnetization: 25-35EMU/g
• Type of Magnetization: Superparamagnetic (no magnetic memory)
• Surface Area: >100m²/g
• Bead Size: 1-4μm diameter
• Settling Rate: 4% in 30 minutes
• Effective Density: 2.5g/mL
• Number of Beads: 1 × 10⁸ beads/mg
• pH Stability: Aqueous solution, above pH 4.0
• Concentration: 5 mg/mL

Streptavidin is a 60kDa protein from Streptomycetes avidinii. The protein is a tetramer having four biotin-binding sites. Unlike avidin, streptvidin has a low isoelectric point (pI=5) and no carbohydrate groups, resulting in low nonspecific binding. The high-affinity interaction between streptavidin and biotin cannot be dissociated efficiently except with very harsh conditions, such as boiling in sample loading buffer for SDS-PAGE or 8M guanidine• HCl, pH 1.5. Consequently, it is often possible to elute binding partners in an interaction complex without also eluting the biotinylated component.

Applications:
• Cell sorting using either positive or negative selection
• Protein purification or immunoassays using either direct or indirect methods