Streptavidin, Recombinant, His-Tag | High Purity & Activity
Streptavidin is a homo-tetrameric protein secreted by Streptomyces avidinii. Streptavidin is used extensively in molecular biology for its extraordinarily high affinity for biotin. The binding of biotin to streptavidin is one of the strongest non-covalent interactions known in nature with a dissociation constant (Kd) of the biotin-streptavidin complex on the order ~10-14 mol/L. The streptavidin/biotin complex is extremely stable over a wide range of temperature and pH. Because streptavidin lacks any carbohydrate modification and has a near-neutral pI, it has the advantage of much lower nonspecific binding than avidin.
Recombinant Streptavidin is produced in E. coli as an N- and C-terminal shortened variant (core streptavidin, amino acids 13-139) and purified by proprietary chromatographic techniques. A single, non-glycosylated polypeptide chain contains a total of 136 amino acids including the N-terminal His-Tag and having a molecular mass of 14.4 kDa. The molecular weight per tetramer is approximately 57.7 kDa.
Catalog # STR-301
SDS-PAGE of Recombinant Streptavidin.
The gel was stained with Coomassie ProStain (Amid Biosciences; catalog # CP-501).
Storage buffer: 40 mM Phosphate buffer, pH 7.2, 120 mM NaCl, 0.05% Tween 20, 20% glycerol
Activity: Greater than 16 U/mg, 1 unit binds 1 µg of d-biotin.
Storage is recommended at -20°C for longer periods of time.
Catalog #: STR-301-5 (5 mg), STR-301-25 (25 mg), STR-301-100 (100 mg).
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This product is for laboratory research use only.
1. Dundas et. al., Streptavidin-biotin technology: improvements and innovations in chemical and biological applications. Appl Microbiol Biotechnol. 2013 97(21): 9343.