Update based on the original article by Regina Huttl, Encyclopedia of Analytical Chemistry, © 2000, John Wiley & Sons, Ltd.
Enzymatic Kinetic Determinations
Published Online: 9 JAN 2014
Copyright © 2000 John Wiley & Sons, Ltd. All rights reserved.
Encyclopedia of Analytical Chemistry
How to Cite
Hüttl, R. and Frank, N. 2014. Enzymatic Kinetic Determinations. Encyclopedia of Analytical Chemistry. 1–22.
- Published Online: 9 JAN 2014
Kinetic methods for analytical applications can be divided into noncatalytic and catalytic methods. Enzyme kinetic determinations are a special type of catalytic methods. Enzymatic reactions are used analytically to determine enzyme activities – for instance, in the diagnosis of diseases, substrate concentrations in the food industry or medicine, and concentrations of effectors – for example, in trace analysis. Owing to the high selectivity of enzymatic analysis, the importance of this method in various fields is growing rapidly. The widest use is observed in clinical chemistry and food chemistry. This article gives only a general survey of the high potential of enzymatic analysis, with references to more detailed literature. Enzymatic reactions are characterized by some special features, explained after the introduction. The theoretical background for kinetic determination is the comprehension of the principles on enzymatic kinetics. In Section 3, the simplest mechanism, outlined by Michaelis and Menten, and several transformations of the equation are described. In this section, two kinetic parameters, enzyme activity and the Michaelis constant, are introduced. Section 4 deals with substances, the so-called effectors, influencing the rate of an enzymatic reaction. Simple mechanisms of these effectors are shown. Different methods for determination of substrates, enzymes, and effectors, illustrated by many examples, are represented in Section 5. While substrate concentrations can be determined using both equilibrium or kinetic methods, the determination of enzymes and effectors can be performed only by kinetic approaches. In the last two sections, the application of enzymes in flow systems and biosensor development are shown.