Amplification of screening sensitivity through selective destruction: Theory and screening of a library of carbonic anhydrase inhibitors

A new method for identifying enzyme inhibitors is to conduct their synthesis in the presence of the targeted enzyme. Good inhibitors form in larger amounts than poorer ones because the binding either speeds up synthesis (target-accelerated synthesis) or shifts the synthesis equilibrium (dynamic combinatorial libraries). Several groups have successfully demonstrated this approach with simple systems, but application to larger libraries is challenging because of the need to accurately measure the amount of each inhibitor. In this report, we dramatically simplify this analysis by adding a reaction that destroys the unbound inhibitors. This works similar to a kinetic resolution, with the best inhibitor being the last one remaining. We demonstrate this method for a static library of several sulfonamide inhibitors of carbonic anhydrase. Four sulfonamide-containing dipeptides, EtOC-Phesa-Phe (4a), EtOC-Phesa-Gly (4b), EtOC-Phesa-Leu (4c) and EtOC-Phesa-Pro (4d), were prepared and their inhibition constants measu...