Homogeneous Enzyme Kinetics

Andrfe Illanes, Claudia Altamirano, and Lorena Wilson  

Enzyme kinetics refers to the quantitative analysis of all factors that determine the catalytic potential of an enzyme. As presented in section 1.3, enzyme activity represents the maximum catalytic potential of an enzyme that is reflected by the initial rate of the catalyzed reaction. Several factors affect the expression of such potential, being the most important the concentrations of active enzyme, substrates and inhibitors, temperature and pH. In the case of insolubilized enzymes or multiphase systems, other variables that reflect mass transfer constraints must be considered. 

School of Biochemical Engineering, Pontificia Universidad Catolica de Valparaiso, Avenida Brasil 2147, Valparaiso, Chile. 

Enzyme activity depends linearly on enzyme protein concentration, even though in some particular circumstances deviations have been observed (Scott 1987). It is however assumed that enzyme activity is proportional to enzyme protein concentration and this is a fundamental principle of enzyme kinetics. A key variable in enzyme kinetics is substrate concentration and its effect constitutes the basis of the hypothesis for enzyme kinetics. 

Conventionally, reaction rates in enzyme kinetics refer always to initial reaction rates where the maximum catalytic potential of the enzyme is expressed and many factors affecting it (i.e. substrate depletion, accumulation of inhibitory products, enzyme inactivation, reverse reaction) are irrelevant (see section 1.3). The quantification of such effects on that maximum catalytic potential is the subject of sections 3.2, 3.3 and 3.4. 

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