Streptavidin: Proteins and Enzymes

Streptavidin is a tetrameric protein purified from Streptomyces sp. that binds very tightly to the vitamin biotin with a Kd of ~ 10-14 mol/l. The high affinity recognition of biotin and biotinylated molecules has made streptavidin one of the most important components in diagnostics and laboratory kits.