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 theinhibitors of a given enzyme target in a compound library. Herein we describe a method for screening the enzyme inhibitorsin 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 wascreated by simply flushing the column with a solution of polyelectrolyte hexadimethrine bromide. The activities of the immobilizedenzymes are assayed by performing the electrophoretic separation and thereafter determining the product of the enzyme-mediatedreaction. Enzyme inhibition can be read out directly from the reduced peak area of product in comparison with that in thereference electropherogram obtained in the absence of any inhibitor.