Tyrosinase from a plant source Amorphophallus companulatus was immobilized on eggshell membrane using glutaraldehyde. Among the three different approaches used for immobilization, activation of eggshell membrane by glutaraldehyde followed by enzyme adsorption on activated support could stabilize the enzyme tyrosinase and was found to be effective. K_m and V_max values for dopamine hydrochloride calculated from Lineweaver-Burk plot were 0.67mM and 0.08mMmin⁻¹, respectively. Studies on effect of pH showed retention of more
than 90% activity over a pH range 5.0–6.5. Membrane bound enzyme exhibited consistent activity in the temperature range 20–45 ^◦C. Shelf life of immobilized tyrosinase system was found to be more than 6 months when stored in phosphate buffer at 4 ◦C. An electrochemical biosensor for dopamine was developed by mounting the tyrosinase immobilized eggshell membrane on the surface of glassy carbon electrode. Dopamine concentrations were determined by the direct reduction of biocatalytically liberated quinone species at −0.19V versus Ag/AgCl (3M KCl). Linearity was observed within the range of 50–250µM with a detection limit of 25µM.