Streptavidin

Streptavidin (CAS Number 9013-20-1) is a tetrameric protein secreted by Streptomyces avidinii which binds firmly to biotin. Streptavidin is wilyde used in molecular biology through its unique high affinity for the vitamin biotin. The dissociation constant (Kd) of the biotin- streptavidin complex is about ~10-15 mol/L. The strong affinity recognition of biotin and biotinylated molecules has made streptavidin one of the most important components in diagnostics and laboratory kits. The streptavidin/biotin system has one of the biggest free energies of association of yet observed for noncovalent binding of a protein and small ligand in aqueous solution (K_assoc = 10**14). The complexes are also extremely stable over a wide range of temperature and pH.

Application

As Streptavidin has a high affinity for biotin, it is employed in a variety of experimental uses, from purifications to standards, to means of detection or pull down experiments

Streptavidin (CAS Number 9013-20-1)) has been tested in Pretargeted immunotherapy. It was conjugated to a monoclonal antibody against cancer cell-specific antigens. When the conjugate is sticked to the cancerous cells, an injection of radiolabelled biotin enables to deliver the radiation only to the cancerous cell.
Two issues have negatively impacted this approach :

  1. The RYD sequence in streptavidin : it generates number of non-relevant binding to other cells such as activated platelets and melanomas
  2. The endogenous biotin binds the streptavidin prior to the injection of the radiolabbeled biotin.

As avidin has no RYD segment, it offers better perspectives in biotechnologies applications e-proteins develops new derivatives to address this new market.

Streptavidin can be produce by e-coli with different specifications

Traptavidin Protein expressed from e-coli , this form presents a higher resistant to temperature and mechanical stability off biotin binding. This form can be compared to the neutralite avidin high temperature

Streptavidin can be produce by e-coli with different specifications

Traptavidin Protein expressed from e-coli , this form presents a higher resistant to temperature and mechanical stability off biotin binding. This form can be compared to the neutralite avidin high temperature

3 types of avidin conjugates

To be efficient in flow cytometry, fluorescent imaging, western blotting, and microplate-based detection, conjugates are used as amplification techniques
for increased signal output and greater sensitivity.

  1. Fluorescent conjugates of avidin/ neutralité avidin/streptavidin are used to detect biotinylated biomolecules such as primary and secondary antibodies, ligands and toxins, or DNA probes for in situ hybridization or bead-based detection.
  2. Enzyme conjugates of avidin/ neutralité avidin/streptavidin, such as HRP and AP, are commonly used in western blotting, ELISA, WB, ICC, IHC and in situ hybridization imaging applications.
  3. Avidin/ neutralite avidin/ Streptavidin-conjugated magnetic beads and resins are employed for isolating Cells, proteins and DNA. Those conjugates are also employed in immunoassays or bio-panning.

Ce site utilise des cookies tiers destinés aux statistiques de fréquentation. En acceptant vous nous permettez de mieux vous connaitre et améliorer votre expérience sur notre site.

Accepter Décliner En savoir plus