DIRECT ELECTROCHEMICAL REDOX OF TYROSINASE AT SILVER ELECTRODES

The direct electron transfer reactions between tyrosinase and silver e lectrode were investigated by using cyclic voltammetry and potential-s tep chronoamperometry as well as current-step chronopotentiometry tech niques. The kinetics of these reactions is quasi-reversible with two e lectron transfer reactions and 0.030 s(-1) apparent electrode reaction rate constant. The results demonstrate that neither electrode surface modification nor the inclusion of mediators is necessary to study the electron transfer reactions of tyrosinase at silver electrodes. Moreo ver, both the anodic and the cathodic currents are linear relationship with the tyrosinase concentration in the rang of 1 x 10(-9) similar t o x 10(-8) mol l(-1). It is possible to be used as a method of analyzi ng tyrosinase concentration. (C) 1997 Elsevier Science B.V.