A supramolecular approach was used for adsorbing a monolayer of adamantane-modified phenylalanine dehydrogenase on beta-cyclo-dextrin-coated Au electrodes. The enzyme electrode (poised at +200 mV vs. Ag/AgCl) showed a linear amperometric response up to 3 mM L-phenylalanine (L-Phe) with a lower detection limit of 15 mu M. The reversible nature of this immobilization approach was confirmed.