Michaelis-Menten equation kinetics

MICHAELIS CONSTANT (APPARENT) MICHAELIS-MENTEN EQUATION L HOPITAL S RULE MICHAELIS CONSTANT MICHAELIS-MENTEN KINETICS PROGRESS CURVE ANALYSIS UNI UNI MECHANISM ZERO-ORDER REACTIONS MICHAELIS-MENTEN KINETICS MICHAELIS-MENTEN EQUATION UNI UNI MECHANISM... 

Equation 11-15 is known as the Michaelis-Menten equation. It represents the kinetics of many simple enzyme-catalyzed reactions, which involve a single substrate. The interpretation of as an equilibrium constant is not universally valid, since the assumption that the reversible reaction as a fast equilibrium process often does not apply. 

The Michaelis-Menten Equation 11-15 is not well suited for estimation of the kinetic parameters and Reananging Equation 11-15 gives various options for plotting and estimating the parameters. 

Saturation kinetics are also called zero-order kinetics or Michaelis-Menten kinetics. The Michaelis-Menten equation is mainly used to characterize the interactions of enzymes and substrates, but it is also widely applied to characterize the elimination of chemical compounds from the body. The substrate concentration that produces half-maximal velocity of an enzymatic reaction, termed value or Michaelis constant, can be determined experimentally by graphing r/, as a function of substrate concentration, [S]. 

The Michaelis-Menten equation is, like Eq. (3-146), a rectangular hyperbola, and it can be cast into three linear plotting forms. The double-reciprocal form, Eq. (3-152), is called the Lineweaver-Burk plot in enzyme kinetics. ... 

If the kinetics of the reaction disobey the Michaelis-Menten equation, the violation is revealed by a departure from linearity in these straight-line graphs. We shall see in the next chapter that such deviations from linearity are characteristic of the kinetics of regulatory enzymes known as allosteric enzymes. Such regulatory enzymes are very important in the overall control of metabolic pathways. 

In evaluation of kinetic parameters, the double reciprocal method is used for linearisation of the Michaelis-Menten equation (5.7.3). 

Kinetic data fitting the rate equation for catalytic reactions that follow the Michaelis-Menten equation, v = k A]/(x + [A]), with[A]0 = 1.00 X 10 J M, k = 1.00 x 10 6 s 1, and k = 2.00 X 10-J molL1. The left panel displays the concentration-time profile on the right is the time lag approach. 

Enzyme kinetics. Data for reactions that follow the Michaelis-Menten equation are sometimes analyzed by a plot of v,/tA]o versus l/[A]o. This treatment is known as an Eadie-Hofstee plot. Following the style of Fig. 4-7b, sketch this function and label its features. 

Coe and Bessell and coworkers studied the metabolic fates of 2-deoxy-2-fluoro-D-glucose (2DFG) and related compounds by using yeast hexokinase (as a model for mammalian hexokinase), and determined the kinetic constants K and V ) of the Michaelis-Menten equation D-glucose 0.17 (K in mAf)> 1 00 (relative value, D-glucose taken as 1) 2DG 0.59 0.11, 0.85 2DFG 0.19 0.03, 0.50 2-deoxy-2-fluoro-D-mannose (2DFM) 0.41 0.05, 0.85 2-deoxy-2,2-difluoro-D-nraZ>//Jo-hexose... 

A classical non-linear model of chemical kinetics is defined by the Michaelis-Menten equation for rate-limited reactions, which has already been mentioned in Section 39.1.1 ... 

The reaction rate for this enzyme kinetics example is expressed by the Michaelis-Menten equation and with product inhibition. 

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... 

The kinetic data from phosphate [28] and proton [58] release experiments were analyzed quantitatively by means of a modified Michaelis-Menten equation assuming activation when only one substrate molecule, S, is bound and inhibition when two substrate molecules are bound to P-gp as described by the following scheme ... 

Mathematically, the Michaelis-Menten equation is the equation of a rectangular hyperbola. Sometimes you ll here reference to hyperbolic kinetics, this means it follows the Michaelis-Menten equation. A number of other names also imply that a particular enzyme obeys the Michaelis-Menten equation Michaelis-Menten behavior, saturation kinetics, and hyperbolic kinetics. 

At high substrate concentrations relative to Km ([S] Km), The Michaelis-Menten equation reduces to v = Vmax, substrate concentration disappears, and the dependence of velocity on substrate concentration approaches a horizontal line. When the reaction velocity is independent of the concentration of the substrate, as it is at Vmax, it s given the name zero-order kinetics. 

Fig. 28.4. Degradation of phenol by a consortium of methanogens, as observed in a laboratory experiment by Bekins et al. (1998 symbols), and modeled using the Michaelis-Menten equation (solid line). Inset shows detail of transition from linear or zero-order trend at concentrations greater than KAy to asymptotic, first-order kinetics below this level. Broken line is result of assuming a first-order rather than Michaelis-Menten law.

The nonlinear form of the Michaelis-Menten equation, 10.2-9, does not permit simple estimation of the kinetic parameters (Km and V ). Three approaches may be adopted ... 

The phosphorylation of each substrate was monitored via a one- or two-substrate reaction in real time and the kinetic parameters (Vmca, Km, kcat, and kcJKm) were determined. Figure 6.54 shows the results of the evaluations of velocity with respect to substrate (Kemptide and CREBtide) concentrations. The data were fitted using the Michaelis-Menten equation to determine the kinetic parameters shown in Table 6.8. The V , of phosphor-Kemptide (105.57 pM/min) was approximately 4.3-fold larger than the V , for CREBtide (24.33 pM/min) although both peptide substrates had similar... 

Michaelis-Arbusov reaction, 19 29, 53, 54 Michaelis constant, 10 255 14 626-627 Michaelis-Menten equation, in kinetic studies, 14 625-627 Michaelis-Menten kinetics, 10 254-255 Michael reaction, 14 570 Michaels addition, of PVA, 25 602 Michelson interferometer, 14 221, 225 Micrinite, 6 707t... 

The scaled elasticities of a reversible Michaelis Menten equation with respect to its substrate and product thus consist of two additive contributions The first addend depends only on the kinetic propertiesand is confined to an absolute value smaller than unity. The second addend depends on the displacement from equilibrium only and may take an arbitrary value larger than zero. Consequently, for reactions close to thermodynamic equilibrium F Keq, the scaled elasticities become almost independent of the kinetic propertiesof the enzyme [96], In this case, predictions about network behavior can be entirely based on thermodynamic properties, which are not organism specific and often available, in conjunction with measurements of metabolite concentrations (see Section IV) to determine the displacement from equilibrium. Detailed knowledge of Michaelis Menten constants is not necessary. Along these lines, a more stringent framework to utilize constraints on the scaled elasticities (and variants thereof) as a determinant of network behavior is discussed in Section VIII.E. 

The parameterization of the remaining reactions is less complicated. For simplicity, the rate v2(TP,ADP) is assumed to follow mass-action kinetics, giving rise to saturation parameters equal to one. Finally, the ATPase represents the overall ATP consumption within the cell and is modeled with a simple Michaelis Menten equation, corresponding to a saturation parameter 6 e [0,1], The saturation matrix is thus specified by four nonzero entries ... 

It has been found experimentally that in most cases v is directly proportional to the concentration of enzyme [.E0] and that v generally follows saturation kinetics with respect to the concentration of substrate [limiting value called Vmax. This is expressed quantitatively in the Michaelis-Menten equation originally proposed by Michaelis and Menten. Km can be seen as an apparent dissociation constant for the enzyme-substrate complex ES. The maximal velocity Vmax = kcat E0. ... 

The expression for the effectiveness factor q in the case of zero-order kinetics, described by the Michaelis-Menten equation (Eq. 8) at high substrate concentration, can also be analytically solved. Two solutions were combined by Kobayashi et al. to give an approximate empirical expression for the effectiveness factor q [9]. A more detailed discussion on the effects of internal and external mass transfer resistance on the enzyme kinetics of a Michaelis-Menten type can be found elsewhere [10,11]. 

Enzyme kinetics Michaelis constant, symbol iCm maximum velocity of an enzyme catalysed reaction, Vm DC inhibitor constant, symbol X Michaelis-Menten equation and graph in the absence and the presence of inhibitors. Lineweaver-Burke and Eadie-Hofstee plots. 

The usual starting point in enzyme kinetics is the Michaelis-Menten equation for the reaction rate v. This also seems a convenient starting point for interpretation of pressure effects on enzyme mechanisms. It will be shown that this formalism may be deceptive if the definitions and interpretations have not been made clear from the beginning. For the mechanism... 

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