COMPARISON OF NATIVE AND CHEMICALLY STABILIZED ENZYMES IN AMPEROMETRIC ENZYME ELECTRODES

Bilayer encagement of lactate dehydrogenase is a suitable tool to improve significantly the thermostability of the enzyme. The long-term stability of encaged lactate dehydrogenase, physically immobilized in front of a mediator-modified electrode for the electrocatalytic oxidation of NADH, and the native enzyme immobilized analogously in front of a similar electrode, is compared in a specially designed flow system which allows the application of an intermittent thermal stress to the enzyme electrodes. The response of the electrode with the encaged enzyme is stable for at least 80 h while that with the native enzyme decreased to about 10% of the initial value.