(Strept)avidin–Biotin Systems

The (strept)avidin–biotin interaction is among the most frequently used affinity binding events exploited for life science research applications. The small-molecule biotin can be used to modify nearly any biomolecule, or other organic molecules, and then facilitate affinity binding to (strept)avidin conjugates or reagents. This strong and highly specific interaction permits the sensitive detection or capture of biotinylated molecules for tracking, imaging, delivery, or purification. Antibodies modified with biotin, for instance, can be used to bind very low concentrations of target molecules and subsequently isolate them for analysis. This chapter reviews the properties, production, and use of (strept)avidin conjugates and biotinylation compounds. It is organized according to the conjugate type being produced or the reactivity of the biotinylation reagent being used.