SOME NEW ENZYME ELECTRODES

Abstract

Electron transfer reactions of redox proteins are studied using electrochemical methods. It is emphasised that the electron transfer occurs without mediation. For many redox proteins, the rate of the electron transfer depends critically on the presence in solution of positively-charged metal ions. In instances where direct electron transfer is very slow, as is the case at present with many potentially useful enzymes, indirect mediated electron transfer is used. Of particular value as mediators are ferrocenes, not only because they take part in rapid, reversible electrochemistry but because of the wide variety of compounds that can be prepared. Their use in a variety of sensors is illustrated in electrochemical assays for glucose and cholesterol and their application in electrochemical immunoassays is illustrated by the analysis of the drug, lidocaine.