Enzyme inhibitor screening by CE with an on-column immobilized enzyme microreactor created by an ionic binding technique.

Enzymes are an important class of drug targets. In the early stage of the drug discovery, the major task is to find out the inhibitors of a given enzyme target in a compound library. Herein we describe a method for screening the enzyme inhibitors in the complex mixtures (such as the natural extracts) by capillary electrophoresis with an on-column immobilized enzyme microreactor. The enzyme molecules are immobilized on the capillary wall via ionic binding with the positively charged coating, which was created by simply flushing the column with a solution of polyelectrolyte hexadimethrine bromide. The activities of the immobilized enzymes are assayed by performing the electrophoretic separation and thereafter determining the product of the enzyme-mediated reaction. Enzyme inhibition can be read out directly from the reduced peak area of product in comparison with that in the reference electropherogram obtained in the absence of any inhibitor.