Chirality sensing with synthetic pores.

A concept to determine enantiomeric excess with synthetic multifunctional pores is introduced. To do so, the poor stereoselectivity of molecular recognition by stimuli-responsive pores is coupled with the stereospecificity of enzymes. With substrates as good and products as poor pore blockers, enzymatic conversion of one enantiomer is shown to readily reveal the concentration of the other one. Calculations suggest that high substrate/product discrimination by the synthetic pores may provide access to the accurate detection of the extreme enantiomeric excess that is of interest in chemistry, pharmacology, and medicine, but otherwise possibly problematic to detect. Validity of the introduced concept is experimentally confirmed with poly-L-glutamate and poly-D-glutamate as enantiomeric substrates with high blockage efficiency, L-glutamate and D-glutamate as enantiomeric products with poor blockage efficiency, subtilisin A as enzyme, and a classical rigid-rod beta-barrel as synthetic pore. (c) 2007 Wiley-Liss, Inc.