streptavidin

strep·ta·vi·din

noun \ˌstrep-ˈtav-əd-ən, -tə-ˈvīd-^ən\

Definition of STREPTAVIDIN

: a protein similar to avidin that is produced by a bacterium of the genus Streptomyces (S. avidinii), has four identical subunits that each bind tightly to a molecule of biotin, and is used especially in the detection of molecules (as nucleic acids or antibodies) linked to a biotin label