Combinatorial screening of enzyme activity by using multiplexed capillary electrophoresis

Efficient and comprehensive screening of enzyme activity was accomplished in a combinatorial array of 96 reaction microvials. Quantitation of the extent of the reaction at well-defined time intervals was achieved by using 96-capillary array electrophoresis coupled with a multiplexed absorption detector. Capillary electrophoresis provides high separation resolution to isolate the product from the reactants. Absorption detection provides universal applicability to combinatorial screening. For the conversion of NADH to NAD+, the catalytic activity of LDH was confirmed to be the highest at pH 7. This scheme should be useful for high-throughput drug discovery, clinical diagnosis, substrate binding, as well as combinatorial synthesis.