Product name:Streptavidin
CAS:9013-20-1
Specification:1MG
Description:
Streptavidin is a 52,800 dalton tetrameric protein purified from the bacterium Streptomyces avidinii. It has an extraordinarily high affinity for biotin (also known as vitamin H); the dissociation constant (Kd) of the biotin-streptavidin complex is on the order of ~10-14 mol/L,making it one of the strongest non-covalent interactions known in nature. It is used extensively in molecular biology and bionanotechnology as, in addition to the high affinity, biotin-binding is resistant to extremes of pH, temperature, organic solvents, denaturants (e.g. guanidinium chloride), detergents (e.g. SDS, Triton) and proteolytic enzymes.
Streptavidin is a tetramer protein with a size of 66KDa. Streptavidin-biotin complex has a dissociation constant of 10-14 mol/L, which is often used in molecular biology. One complete SA peptide chain contains 159 amino acid residues with a molecular weight of 16450.
Streptavidin molecule is composed of four identical peptide chains. In the amino acid composition, the content of glycine and alanine is relatively large, and the active group binding biotin is also the tryptophan residue in the peptide chain. Streptavidin is a slightly acidic (pH6.0) protein without any sugar groups. Under the action of proteolytic enzyme, Streptavidin can break between 10-12 at the N terminal and 19-21 at the C terminal, and the formed core Streptavidin still maintains the complete ability of binding biotin. The active unit of Streptavidin is also expressed in the amount required to bind 1 mug of biotin, and the maximum activity of 1mg of Streptavidin is 18U.