• a-hemolysin • Gramicidin • Alamethicin • Resistive pulse • Current blockage • Translocation time • Sojourn time • Biosensing • BLM • Planar lipid bilayer

Abstract Electrical current recordings through electrolyte-filled nanopores (so called resistive pulse-sensing experiments) are attracting increasing attention for identifying and characterizing biomolecules. The majority of the work employing this method so far has focused on detection of oligonucleotides, polymers, and viruses. Most recently nanopores have been used to detect single proteins. This chapter reviews the very first attempts to use nanopores for characterizing properties of proteins that relate to their activity. The emphasis lies on those studies that provided quantitative information on activity-related properties of proteins, such as protein conformation, ligand binding, and enzyme activity. Nanopore-based studies have tremendous poten-tial for investigating the function of proteins because the technique is capable of interrogating individual proteins at high-throughput without requiring labeling