Recombinant Streptavidin is a homo-tetrameric protein variant (core streptavidin, amino acids 13-139) produced in E. coli and purified using proprietary chromatographic techniques. Consisting of a single, non-glycosylated polypeptide chain of 136 amino acids, it includes an N-terminal His-Tag and features a molecular mass of 14.4 kDa (approximately 57.7 kDa per tetramer).

Streptavidin is widely used in molecular biology due to its extraordinarily high affinity for biotin ($\text{K}_\text{d} \approx 10^{-14} \text{ mol/L}$). Because it lacks carbohydrate modifications and maintains a near-neutral pI, it yields significantly lower non-specific binding compared to native avidin.

Key Features & Applications:

• High Affinity & Stability: The streptavidin-biotin complex remains exceptionally stable across broad pH and temperature ranges.

• Versatile Workflows: Ideal for affinity protein purification, immunoassays, Western blotting, ELISA detection, histochemistry, FISH, and cellular imaging.

• Convenient Tagging: Equipped with an N-terminal His-Tag for seamless detection or secondary immobilization.

Specifications:

• Activity: Greater than 16 U/mg (1 unit binds 1 µg of D-biotin).

• Storage Buffer: 40 mM Phosphate buffer (pH 7.2), 120 mM NaCl, 0.05% Tween 20, 20% glycerol.

• Formulation Sequence: MHHHHHHKLAEAGITGTWYNQLGSTFIVTAGADGALTGTYESAVGNAESRYVLTGRYDSAPATDGSGTALGWTVAWKNNYRNAHSATTWSGQYVGGAEARINTQWLLTSGTTEANAWKSTLVGHDTFTKVKPSAAS

• Catalog Numbers: STR-301-1 (1 mg), STR-301-5 (5 mg), STR-301-25 (25 mg), STR-301-100 (100 mg).

• Intended Use: For research use only (RUO).