A story about biotin-avidin affinity and how it accelerate small molecule drug discovery


Biotin is a type of water soluble vitamin, also called vitamin B7. Although it's an essential substance for all species, only baceria, yeast, mold, algae and certain plants are capable of producing it, leaving the mammalian species depend on external sources. Did you know that biotin deficiency attributes to congenital of nutritional abnormalities and tends to cause brittle nails, loss of appetite, hair loss and predisposition to skin infection? Affinity between biotin and avidin is said to be a million-fold stronger than an antigen-antibody interation. If you consume a large amount of raw egg white containing a lot of avidin, the strong avidin-biotin reaction prevents absorption of biotin in your syste, resulting in serious biotin defficiency. Streptavidin, which has a similar structure to avidin, exhibits the same strong affinity to biotin, while its characteristics result in much less nonspecific binding.

The strong binding between streptavidin and biotin is an invaluable asset widely utilized in biochemical experiments for many applications. One major example is its use in evaluation of intermolecular interactions based on the surface plasmon resonance (SPR) detection principle. Biacore AB Corporation (presently GE healthcare) was the first company to develop SPR measuring insturmentation. A simple interaction experiment involves immobilizing one molecule of a binding pair ("ligand") on the sensor chip surface and injecting a series of concentrations of its partner ("alanyte") accross the surface. Changes in the refractive index at the surface where the binding occurs are detected. Real time monitoring of association and dissociation between two binding partners generates analytical data for kinetics and affinity of molecular interaction. If your ligand is a protein, it's advisable to choose a biotinylated protein because it wil make your immobilization of a ligand onto a streptavdin covalently-attached sensor chip much easier with stronger affinity. This advantageous mechanism is also useful for FRET, ELISA and AlfaScreen technology (Perkin Elmer). In addition, biotin's smaller molecular weight, compared to other tags such as GST and MBP, makes it less prone to interfare with ligand-analyte interaction, ultimately leading to higher detection sensitivity.

Knowing the key role biotin has played in biochemical experiments, we invite you to join the many customers who utilize Carna's biologically produced biotnylated protein kinases. These exclusive products, a single biotin attached to the N-turminus and >80% guaranteed-purity, will save you time and expense when you are establishing key binding experiments to better understand your small molecules and will allow you to generate more reliable data with low background. You can find all biotinylated kinases available from Carna in this web shop!

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