Fluoro-glycosyl acridinones are ultra-sensitive active site titrating agents for retaining β-glycosidases.

Novel fluorogenic 2-deoxy-2-fluoroglycosyl acridinone active site titrating reagents were synthesised and kinetic parameters determined for their inactivation of two retaining β-glucosidases, a β-galactosidase, a β-xylosidase and several cellulases. Fluorescence-monitored active site titration using this class of reagents reliably measured active enzyme concentrations down to 3 nM.