The electrochemistry of redox enzymes

Abstract

The work presented in this thesis is of two types. Firstly methods for the electrochemical immobilisation of redox enzymes in organic polymers are described. The electrochemical monitoring of the immobilised enzyme reaction by detection of one of the enzyme's products is discussed, and the results obtained for such a system under a variety of experimental conditions are presented. A good understanding of the way in which such a system operates' was obtained by using a specially developed kinetic model., This model is explained fully in the theory chapter of this thesis. A variety of organic polymers were used in the electrochemical immobilisation process, with varying degrees of success. The flexibility of this approach is demonstrated by the use of a variety of immobilisation matrices and also by the development of bienzyme and bilayer devices. The final experimental chapter presents work on the covalent modification of redox enzymes with a variety of, redox centres based. on ferrocene. Although attempts to electrochemically immobilise a modified enzyme were not successful, some interesting information about the kinetic behaviour and stability of a series Of modified enzymes was obtained. An indication of possible work forming an extension to this thesis is given in the final part of this thesis. The electrochemical immobilisation techniques and the procedure for covalently modifying, enzymes using electroactive, groups are relatively recent ideas. Much work remains to be done before a better understanding of these systems is gained