Avidin is a glycoprotein with a molecular weight of ~62.4kD. Avidin is a biotin binding protein that shows high sequence homology in birds, reptiles and amphibians. Hen egg white avidin is a tetrameric protein composed of four identical subunits, each with the ability to bind biotin with high affinity and specificity (Kd ~ 1015 M). In biotechnology, the functional consequence of tetrameric biotin binding is signal amplification. Biotin-avidin bridging is a great way to increase signal strength while maintaining specificity. The sequence of avidin only shows 30% homology with streptavidin, and anti-avidin and anti-streptavidin antibodies are not immunologically cross reactive. Biotin is widely used throughout the biotechnology industry to conjugate proteins for biochemical assays. Biotin's small size typically does not affect the biological activity of protein upon biotinylation. Biotinylated proteins of interest can be enriched from a sample due to highly stable interactions.
Intended for research use only. Not for use in human, therapeutic, or diagnostic applications.