Lactate dehydrogenase (LDH) was reversibly denatured using 1-ethyl-3- methylimidazolium tetrafluroborate (IL), in the presence and absence (respectively) of water. LDH was reversibly denatured and “wired” at the same time with flavin adenine dinucleotide (FAD), an intrinsic group of the enzyme. The modified enzymes, after renaturation, were assayed and the activities compared with that of the starting LDH. In a second assay, they were evaluated for potential use in enzyme electrodes. Immobilization of the IL-modified LDH was done using different methods and the results are discussed comparatively. The performance of the “wired” LDH is also compared to that of the enzyme using as mediator FAD in solution. The electrodes were evaluated also for catalytic effect, linearity and stability. The IL-modified LDH showed promise for use in both analytical and synthetic applications.