Kinetics of enzymes

Perez-Bendito, D. Silva, M. Kinetic Methods in Analytical Chemistry. Ellis Horwood Chichester, England, 1988. Additional information on the kinetics of enzyme catalyzed reactions maybe found in the following texts. 

This chapter solely reviews tlie kinetics of enzyme reactions, modeling, and simulation of biochemical reactions and scale-up of bioreactors. More comprehensive treatments of biochemical reactions, modeling, and simulation are provided by Bailey and Ollis [2], Bungay [3], Sinclair and Kristiansen [4], Volesky and Votruba [5], and Ingham et al. [6]. 

Kinetics of Enzyme-Catalyzed Reactions Involving Two or More Substrates... 

Each of the processes shown in Figure 2.8 can be described by a Michaelis-Menten type of biochemical reaction, a standard generalized mathematical equation describing the interaction of a substrate with an enzyme. Michaelis and Men ten realized in 1913 that the kinetics of enzyme reactions differed from the kinetics of conventional... 

The kinetics of enzyme reactions were first studied by the German chemists Leonor Michaelis and Maud Menten in the early part of the twentieth century. They found that, when the concentration of substrate is low, the rate of an enzyme-catalyzed reaction increases with the concentration of the substrate, as shown in the plot in Fig. 13.41. However, when the concentration of substrate is high, the reaction rate depends only on the concentration of the enzyme. In the Michaelis-Menten mechanism of enzyme reaction, the enzyme, E, and substrate, S, reach a rapid preequilibrium with the bound enzyme-substrate complex, ES ... 

The kinetics of enzyme-catalyzed readions resemble those of the heterogeneous readions discussed in the previous sections. However, because in practice there are a few charaderistic differences in how the equations are handled, we treat the enzymatic case separately. 

Protoplast fusion induced by polyethyleneglycol and Ca was carried out between two auxotrophic mutants of Aspergillus sp. CH-Y-1043. The hybrids obtained showed significant differences in endopectinase activity and morphology compared to the prototrophic strain. Strains grown on lemon peel showed production improvement with respect to the parental strain. Since H15 hybrid showed up to 90% higher endopectinase production than the wild type CH-Y-1043, kinetics of enzyme production in Fernbach flasks and Fermentor (14L) by H15 were determined. 

This equation is fundamental to all aspects of the kinetics of enzyme action. The Michaelis-Menten constant, KM, is defined as the concentration of the substrate at which a given enzyme yields one-half of its maximum velocity. is the maximum velocity, which is the rate approached at infinitely high substrate concentration. The Michaelis-Menten equation is the rate equation for a one-substrate enzyme-catalyzed reaction. It provides the quantitative calculation of enzyme characteristics and the analysis for a specific substrate under defined conditions of pH and temperature. KM is a direct measure of the strength of the binding between the enzyme and the substrate. For example, chymotrypsin has a Ku value of 108 mM when glycyltyrosinylglycine is used as its substrate, while the Km value is 2.5 mM when N-20 benzoyltyrosineamide is used as a substrate... 

Laidler, K. J., The Chemical Kinetics of Enzyme Action, Clarendon Press, Oxford, 1958. 

Nannipieri P, Gianfreda L (1999) Kinetics of enzyme reactions in soil environments. In Huang PM, Senesi N, Buffle J (eds) Structure and surface reactions of soil particles, vol 4, IUPAC series on analytical and physical chemistry of environmental systems. Wiley Chichester UK, pp 449-479... 

The subject of biochemical reactions is very broad, covering both cellular and enzymatic processes. While there are some similarities between enzyme kinetics and the kinetics of cell growth, cell-growth kinetics tend to be much more complex, and are subject to regulation by a wide variety of external agents. The enzymatic production of a species via enzymes in cells is inherently a complex, coupled process, affected by the activity of the enzyme, the quantity of the enzyme, and the quantity and viability of the available cells. In this chapter, we focus solely on the kinetics of enzyme reactions, without considering the source of the enzyme or other cellular processes. For our purpose, we consider the enzyme to be readily available in a relatively pure form, off the shelf, as many enzymes are. 

For these reasons, in the experimental study of the kinetics of enzyme-catalyzed reactions, T, shear and PH are carefully controlled, the last by use of buffered solutions. In the development, examples, and problems to follow, we assume that both T and pH... 

Koch, A. L. and Coffman, R. (1970). Diffusion, permeation, or enzyme limitation a probe for the kinetics of enzyme induction, Biotechnol. Bioeng., 12, 651-677. 

W. W. Cleland. The kinetics of enzyme catalyzed reactions with two or more substrates or products. I. Nomenclature and rate equations. Biochim. Biopkys. Acta. 67, 104 137 (1963). 

Experimental studies on the effect of substrate concentration on the activity of an enzyme show consistent results. At low concentrations of substrate the rate of reaction increases as the concentration increases. At higher concentrations the rate begins to level out and eventually becomes almost constant, regardless of any further increase in substrate concentration. The choice of substrate concentration is an important consideration in the design of enzyme assays and an understanding of the kinetics of enzyme-catalysed reactions is needed in order to develop valid methods. 

In the remaining part of our presentation of the formal kinetics of enzyme isotope effects a few more complicated examples will be discussed. The methods developed here should be also useful for unraveling other complicated enzyme reactions, and in reading and understanding the modern literature on isotope effects on enzymatic processes. 

Laidler, K. J., and Bunting, P. S. (1973). The Chemical Kinetics of Enzyme Action. Oxford Univ. Press (Clarendon), London and New York, le Noble, W. J. (1967). Prog. Phys. Org. Chem. 5, 207. 

Henderson PJ. 1972. A linear equation that describes the steady-state kinetics of enzymes and subceUular particles interacting with tightly bound inhibitors. Biochem J 127 321. 

The kinetics of enzyme-catalyzed reactions (i. e the dependence of the reaction rate on the reaction conditions) is mainly determined by the properties of the catalyst, it is therefore more complex than the kinetics of an uncatalyzed reaction (see p.22). Here we discuss these issues using the example of a simple first-order reaction (see p.22)... 

Feng S, Li C, Xu X, Wang X, Screening strains for directed biosynthesis of [[)] -D-mono-glucuronide-glycytthizin and kinetics of enzyme production,/Afo/ Catal B EnzymolYi. Si—GJ, 2006. 

H. T. F. Wong (1975) Kinetics of Enzyme Mechanisms, Academic Press, New York. 

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