Immobilized tyrosinase reactor for on-line HPLC application: Development and characterization

Mushroom tyrosinase was covalently bonded with glutaraldehyde, as activating agent, to aminopropyl-controlled pore glass support by “in situ” immobilization technique. The Schiff's base double bond reduction with sodium cyanoborohydride was made as innovation. Catalytic activity and stability of the chromatographic reactor were evaluated using d,l-3,4-dihydroxyphenylalanine as substrate. The tyrosinase-IMER was characterized by investigation of various parameters influencing the enzymatic activity (pH, temperature, ionic strength and organic solvents). In addition kinetic measurements showed that, by removal of the external diffusional limitation, the enzyme selectivity towards substrate was improved whereas the activity was comparable with respect to that of free enzyme.