Molecular glues for manipulating enzymes: Trypsin inhibition by benzamidine-conjugated molecular glues

Abstract

© The Royal Society of Chemistry 2015. Water-soluble bioadhesive polymers bearing multiple guanidinium ion (Gu⁺) pendants at their side-chain termini (Glue<inf>n</inf>-BA, n = 10 and 29) that were conjugated with benzamidine (BA) as a trypsin inhibitor were developed. The Glue<inf>n</inf>-BA molecules are supposed to adhere to oxyanionic regions of the trypsin surface, even in buffer, via a multivalent Gu⁺/oxyanion salt-bridge interaction, such that their BA group properly blocks the substrate-binding site. In fact, Glue<inf>10</inf>-BA and Glue<inf>29</inf>-BA exhibited 35- and 200-fold higher affinities for trypsin, respectively, than a BA derivative without the glue moiety (TEG-BA). Most importantly, Glue<inf>10</inf>-BA inhibited the protease activity of trypsin 13-fold more than TEG-BA. In sharp contrast, ^mGlue<inf>27</inf>-BA, which bears 27 Gu⁺ units along the main chain and has a 5-fold higher affinity than TEG-BA for trypsin, was inferior even to TEG-BA for trypsin inhibition.