Stabilisation of tyrosinase by reversed micelles for bioelectrocatalysis in dry organic media

• The enzymatic and bioelectrocatalytic activity of tyrosinase from mushrooms was studied in a system of reversed micelles formed by Aerosol OT (AOT) in hexane. The optimal catechol oxidising activity of tyrosinase incorporated in reversed micelles was found at a hydration degree of w(0) = 25. The catalytic activity was comparable with tyrosinase activity in aqueous media. When immobilized at an Au electrode, either directly or in reversed micelles, tyrosinase exhibited a similar efficiency of the bioelectrocatalytic reduction of O-2 mediated by catechol; however, a rapid decrease in the activity correlated with the destruction of reversed micelles and/or the removal of tyrosinase from the electrode surface. The system containing tyrosinase in reversed micelles with caoutchouk, spread on the surface of the An electrode and successively covered with a Nafion(R) membrane layer, was found to result in stable tyrosinase-modified electrodes, which were resistant to inactivation in dry acetonitrile. The proposed technique offers possibilities for further development of highly active and stable surfactant/enzyme-modified electrodes for measurements carried out in organic solvents. (C) 2002 Elsevier Science B.V. All rights reserved.

Ämnesord

NATURVETENSKAP  -- Kemi -- Analytisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Analytical Chemistry (hsv//eng)

Nyckelord

acetonitrile

bioelectrocatalysis in organic media

tyrosinase

reversed micelle

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