Catalytic Activity of Native Enzymes during Capillary Electrophoresis: An Enzymatic *Microreactor'l

This work evaluates the use of a plug of enzyme, migrating in an electrophoresis capillary under nondenaturing conditiong, to convert substrate (which may be injected onto the capillary as a separate plug or included in the electrophoresis buffer) to product. This concept is demonstrated using two systems: the irreversible oxidation of glucose-G-phosphate (glc-6-P) to 6-phosphogluconate using glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49) and either NAD or NADP as cofactor, and the reversible conversion of ethanol to acetaldehyde using yeast alcohol dehydrogenase (YADH, EC 1.1.1.1) and NAD(H) as cofact,rr. These procedures illustrate the use of the electrophoresis capillary as a microreactor in which reactants and products are moved into and out of contact with one another based on differences in electrophoretic mobilities. It offers a useful approach to the manipulation of enzymes and enzyme-catalyzed reactions on a microscale.