The avidin-biotin system
The major direction of my early work in this field was devoted to the study of the avidin-biotin complex and its general use as a tool in the biological sciences. The main reason for interest in this system is two-fold: (a) The interaction between avidin (or streptavidin) and biotin exhibits the highest known affinity (Ka ~ 1015 M-1) between a ligand and a protein (1), and (b) the avidin-biotin system has become a universal tool in many biotechnological applications (Figure 1). We were the first to biotinylate various macromolecules, such as antibodies and lectins. We also designed and synthesized a variety of additional group-specific biotinylating reagents and developed many new applications of the avidin-biotin system (Figure 2).