biotinavidin

Biotin and avidin are proteins with a remarkable affinity for each other. Biotin, also known as vitamin B7, is a water-soluble vitamin crucial for various metabolic processes in living organisms. Avidin is a protein found in egg whites and other sources. The binding interaction between biotin and avidin is one of the strongest non-covalent interactions known in nature, with an association constant in the femtomolar range.

This exceptionally strong and specific binding has made the biotin-avidin system a widely used tool in molecular biology, biochemistry, and diagnostics. In many applications, biotin is attached to a molecule of interest, such as an antibody, DNA probe, or drug. This biotinylated molecule can then be detected or captured using avidin or a related protein like streptavidin, which has similar binding properties but is less prone to non-specific binding.

The biotin-avidin system is employed in numerous techniques, including enzyme-linked immunosorbent assays (ELISAs), Western blotting, immunohistochemistry, affinity chromatography, and magnetic bead-based separations. The high specificity ensures that the biotinylated molecule is selectively bound by the avidin conjugate, leading to sensitive and accurate detection or purification. The stability of the biotin-avidin complex allows for harsh washing steps without dissociation, further enhancing its utility in various experimental conditions.