Uses of Enzymes in Analytical Chemistry

stry* Ar,a.N TowNsnsNo Department of Chemistry, Unive$ity of Hull, Hull HU6 7RX The paper reviews the basic features of enzyme-catalysed reactions, and distinguishes between the optimal conditions required for monitoring enzyme concentrations (and, therefore, those of inlfbitors and activators) and sub- strates. Recent advances are emphasised, including insolubilised enzyme and bacterial electrodes, enzyme-based sample decomposition, drug and pesticide detection, and apo-enzyme activation, as well as more common applications. Enzymes are naturally-occurring protein-based macromolecules which catalyse reactions of great selectivity and sensitivity. There are several general categories of enzyme such as those which catalyse particular redox reactions, or cause hydrolysis of certain molecules, Individual enzymes include lactate dehydrogenase, which catalyses the oxidation oflactate to pyruvate, and glucose oxidase, which catalyses the oxidation of glucose by oxygen to gluconic acid. Well over 1000 enzymes are known. The glucose oxidation (which occurs in aqueous solution with molecular oxygen at room temperature and forms hydrogen peroxide) is a good illustrative example of how very s