Discovery of small molecule inhibitors of xyloglucan endotransglucosylase (XET) activity by high-throughput screening

Xenobiotics that inhibit the cell-wall-remodelling enzyme activity, xyloglucan endotransglucosylase (XET), would be a valuable tool in 'chemical genetics' for elucidating its biological roles. By screening 4216 small molecules in a dot-blot assay on paper-immobilised xyloglucan, we discovered 45 compounds that inhibited or promoted XET activity. The most effective inhibitors were singlet oxygen generators.