Avidin is a tetrameric biotin-binding protein produced in the oviducts of birds, reptiles and amphibians and deposited in the whites of their eggs.

[5] Functional avidin is found in raw egg, but depending on the amount of heat it is exposed to during cooking, the quantity of molecules available for binding biotin can change.

[12][13][14][15] Soon after, researchers Bayer and Wilchek developed new methods and reagents to biotinylate antibodies and other biomolecules,[16][17] allowing the transfer of the avidin-biotin system to a range of biotechnological applications.

[citation needed] Avidin immobilized onto solid supports is also used as purification media to capture biotin-labelled protein or nucleic acid molecules.

For a single high affinity biotin binding site without crosslinking, a monovalent version of avidin's distant relative, streptavidin, may be used.

[21] A 1966 study published in Biochemical and Biophysical Research Communications found that the structure of avidin remains stable at temperatures below 70 °C (158 °F).

The assay surmised that cooking times were not sufficient to adequately heat all cold spot areas within the egg white.

[21] The biotin-binding properties of avidin were exploited during the development of idrabiotaparinux, a long-acting low molecular weight heparin used in the treatment of venous thrombosis.

By adding a biotin moiety to the idraparinux molecule, idrabiotaparinux was formed; its anticoagulant activity in the setting of a bleeding event can be reversed through an intravenous infusion of avidin.