Streptavidin

  • CAS Number: 9013-20-1

Streptavidin is a protein that is produced by bacteria of the species Streptomyces avidinii. The protein composed of four identical protein subunits having a molecular weight of about 60,000 daltons; each of the four sub-units may each bind with very high affinity (Ka ~ 1014-1015 M-1), a molecule of the vitamin biotin. The streptavidin-biotin bond is one of the strongest known non-covalent biological bindings. In contrast to avidin, which can also bind biotin, streptavidin has an isoelectric point in the neutral range ( 7.0, in other sources also pI = 5-6 ). Due to its lower overall charge and streptavidin because is not a glycoprotein and therefore does not bind to carbohydrate - receptors, non-specific binding to streptavidin systems are less common than in the use of avidin.

Structure

The primary structure of the monomer, so each of the four identical subunits is composed of 159 amino acids and has a molecular mass of 16,807 Da.

Application

The streptavidin / biotin interaction is utilized in a wide variety of methods in biochemistry, immunology, and molecular biology:

  • Affinity chromatography
  • Immunohistochemistry
  • Gene probe, single base extension
  • DNA chip technology,

Swell

  • Protein
CAS registry number Streptomycetaceae Hybridization probe
751615
de