Thesis presented December 20, 2022

Abstract:
Glycoside hydrolases (glycosidases) belong to a vast family of enzymes which catalyse the hydrolysis of glycosidic bonds. As ubiquitous enzymes, they are involved in a wide range of biological processes and can be related to several diseases. Besides, such enzymes are of great interest as valuable biocatalysts for food industry and for developping energy supply from biomass.
In the last decades, genomic analysis made possible the identification of new glycosidases in a large variety of living organisms. However, the structure and the function of most of these glycosidases remains unknown to date, which is a limitation to the growth of new potential applications. Accordingly, there is a current need for new tools to characterize both function and structure of glycosidases, in order to improve the understanding of this vast family of enzymes. During this thesis we have harnessed molecules from the class of iminosugars to conceive new probes for glycosidases, with the aim to design biochips that could be used to detect and isolate such enzymes without damaging their structures.
Three families of probes based on different iminosugar cores were synthesized through different pathways, including diastereoselective nitrone alkynylation and 1,6-enyne-cycloizomerisation. The affinity of these probes for glycosidases was determined by inhibition assays on several commercial enzymes. The different probes were then grafted on a gold surface by pyrrole electrocopolymerization to access biochips, and the latter were used to detect a model enzyme in solution (rice α-glucosidase).

Keywords:
Glycosidases, Iminosugars, Selective inhibitors, multiplexed array, SPRi