Enzyme Kinetics Basics

In order to understand the mechanisms of the enzymatic process and also predict the reaction characteristics, one needs to understand the kinetics of the reaction. The important factor that effects the enzyme reaction is the availability and concentration of the substrates. An important model that gives a mathematical relationship is the Michaelis-Menten and Hill equation. The equation is denoted as 

The linear form of this equation is denoted hy the Lineweaver-Burk or double reciprocal plot, which is derived from the Michaelis-Menten and Hill equation and is denoted as  

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Before beginning a quantitative treatment of enzyme kinetics, it will be fruitful to review briefly some basic principles of chemical kinetics. Chemical kinetics is the study of the rates of chemical reactions. Consider a reaction of overall stoichiometry... 

The general theory of enzyme kinetics is based on the work of L. Michaelis and M. L. Menten, later extended by G. E. Briggs and J. B. S. Haldane.la The basic reactions (E = enzyme, S = substrate, P = product) are shown in equation 2.1 ... 

Aiming to construct explicit dynamic models, Eqs. (5) and (6) provide the basic relationships of all metabolic modeling. All current efforts to construct large-scale kinetic models are based on an specification of the elements of Eq (5), usually involving several rounds of iterative refinement For a schematic workflow, see again Fig. 4. In the following sections, we provide a brief summary of the properties of the stoichiometric matrix (Section III.B) and discuss the most common functional form of enzyme-kinetic rate equations (Section III.C). A selection of explicit kinetic models is provided in Table I. TABLE I Selected Examples of Explicit Kinetic Models of Metabolisin 1 ... 

For the time being, our basic understanding of pressure effects is far from complete. However, some new developments concerning theory and application have occurred over the years. A short theoretical treatment of pressure effects was presented almost 30 years ago (Laidler, 1951). In this article we will present an extensive treatment of the present theoretical basis for pressure effects, incorporating contemporary knowledge of enzyme kinetics, physical biochemistry, and high-pressure theory. The theoretical level in this field is still not very sophisticated, but it is important enough so that theoretical considerations should be applied when future experiments are planned. 

Abstract Neuroscientists may wish to quantify an enzyme activity for one of many reasons. In order to do so, the researcher must be able to set up an assay appropriately, and this requires some understanding of the kinetic behavior of the enzyme toward the substrate used. Furthermore, such an understanding is vital if the inhibitory effects of a drug are to be assessed appropriately. This chapter outlines key principles that must be adhered to, and describes basic approaches by which rather complex kinetic data might be obtained, in order that enzyme kinetics and inhibitor kinetics might be studied successfully by the nonexpert. 

Enzyme-based biochemical networks can be designed and analyzed using basic principles of enzyme kinetics and compartmental analysis procedures. 

The effects of these factors and the means by which they are studied are usually described as enzyme kinetics. The basic information required to study enzyme kinetics is as follows. 

ENZYME KINETIC EQUATIONS MICHAELIS-MENTEN EQUATION UNI UNI MECHANISM ENZYME RATE EQUATIONS 1. The Basics... 

Hammes, G.G. (1992) Enzyme Catalysis and Regulation. New Yoik Academic Press. Keleti, T. (1986) Basic Enzyme Kinetics. Budapest The Publising House of the Hungarian Academy of Sciences. 

Keleti, T. (1986) Basic Enzyme Kinetics, Akademic Kiado, Budapest. 

This chapter describes the different types of batch and continuous bioreactors. The basic reactor concepts are described as well as the respective basic bioreactors design equations. The comparison of enzyme reactors is performed taking into account the enzyme kinetics. The modelhng and design of real reactors is discussed based on the several factors which influence their performance the immobilized biocatalyst kinetics, the external and internal mass transfer effects, the axial dispersion effects, and the operational stabihty of the immobilized biocatalyst. 

It is found experimentally in most cases that v is directly proportional to the concentration of enzyme, [E]0. However, v generally follows saturation kinetics with respect to the concentration of substrate, [S], in the following way (Figure 3.1). At sufficiently low [S], v increases linearly with [S]. But as [S] is increased, this relationship begins to break down and v increases less rapidly than [S] until, at sufficiently high or saturating [S], v tends toward a limiting value termed Vmax. This is expressed quantitatively in the Michaelis-Menten equation, the basic equation of enzyme kinetics ... 

The results from Basic Protocol 1 are expected to be consistent with traditional initial velocity assumptions for enzyme kinetics (unit cl /). The assay, as presented, includes four time points (along with a zero-time value) in order to establish the relationship between reaction time and product formed. Representative data, demonstrating the hyperbolic nature of this relationship, are presented in Figure C1.2.3. In this case, only the initial time points at the lowest enzyme concentration are consistent with the linear initial velocity assumption. If... 

Two principal methods are widely used for the assay of DPOs. For enzyme kinetic studies, the most appropriate methods are polarographic and use an 02 electrode (Basic Protocol), which allows the direct measurement of the rate of utilization of oxygen and a true comparison of different phenolic substrates. Minor disadvantages of this method are that it requires more specialized equipment and that assays can only be carried out one at a time. Nevertheless it has proven to be the basis of some excellent undeigraduate biochemical laboratory experiments. 

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