Reagentless recycling of pyruvate oxidase on a conducting polymer-modified electrode

The enzyme pyruvate oxidase (PyOD) covalently immobilized on an original conducting copolymer poly(5-hydroxy-1,4-naphthoquinone-co-5-hydroxy-3-thioacetic-1,4-naphthoquinone acid) can be recycled under anaerobic conditions, at +0.1 V versus SCE. It is first demonstrated that the quinone group is an efficient co-substrate for PyOD in homogeneous conditions, then this efficiency is preserved when the quinone group is embedded in the polymer structure. The copolymer remains efficient even in aerated media. The low working potential avoids side-oxidations of interfering species as ascorbic acid or salycilate.