Biotin, a 244Da vitamin (Vitamin H) molecule, exhibits an extraordinary binding affinity for avidin (Ka=10¹âµM-¹) and streptavidin (Ka=10¹âµM-¹). Biotin and (strept)avidin interaction is rapid. Once the bond is established, it can survive up to 3M guanidine-hydrochloride and extreme levels of pH. Biotin-avidin bonds can only be reversed by denaturing the avidin protein molecule with 8M guanidine-hydrochloride at a pH of 1.5, or by boiling in SDS Page Sample Loading Buffer.
Streptavidin is a tetrameric protein containing 4 biotin binding sites. In many respects, streptavidin is similar to avidin, but it does not contain a carbohydrate, and its molecular weight (about 60kDa) is slightly lower. The solubility of streptavidin (isoelectric pH5) in aqueous buffer is much lower than avidin; however, the binding of streptavidin to biotin is very similar to that of avidin.
The advantage of streptavidin is that the lack of carbohydrates significantly reduces the amount of non-specific binding.
The streptavidin used for immobilization on porous 6% cross-linked agarose is a recombinant form, with a mass of 53kDa and a near neutral pH. The streptavidin is covalently coupled to the agarose, resulting in minimal leaching, and is stable over a pH range of 2 to 11.
The Streptavidin Resin is designed for the single-step, small and large scale affinity purification of proteins, antibodies and other molecules with a biotin tag. The resin can also be used for assay development and immunopreciptations of proteins using biotin labeled antibodies.
Our streptavidin is supplied as resin slurry or in a 1ml spin-column format.
Specific Binding and Elution Buffers are also available.
Click here to request bulk or custom sizes.
Features
- Recombinant streptavidin covalently coupled to ~6% cross-linked agarose for minimal leaching
- Single-step, small & large scale affinity purification
- Supplied as resin slurry or in spin-column format
- Binding Capacity: 15-30 µg biotin/ml resin
- Ligand Density: > 1 mg biotin-BSA/ml resin
- Stability Range: pH2-11
Applications
- Immunopreciptation of proteins using biotin labeled antibodies
- Assay development (pull down assays) using biotinylated proteins
- Purification of biotinylated molecules, including: proteins, antibodies, DNA, carbohydrates & other molecules with a biotin tag