Kinetics Lineweaver-Burk plot

Michaelis-Menten Kinetics Lineweaver-Burk Plots Enzyme Inhibition... 

The three reversible mechanisms for enzyme inhibition are distinguished by observing how changing the inhibitor s concentration affects the relationship between the rate of reaction and the concentration of substrate. As shown in figure 13.13, when kinetic data are displayed as a Lineweaver-Burk plot, it is possible to determine which mechanism is in effect. 

Lineweaver-Burk plot a graphical means for evaluating enzyme kinetics, (p. 638)... 

Lineweaver-Burk plot Method of analyzing kinetic data (growth rates of enzyme catalyzed reactions) in linear form using a double reciprocal plot of rate versus substrate concentration. 

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. ... 

First draw both Lineweaver-Burk plots and Hanes-Woolf plots for the following a Monod-Wyman-Changeux allosteric K enzyme system, showing separate curves for the kinetic response in (1) the absence of any effectors (2) the presence of allosteric activator A and (3) the presence of allosteric inhibitor I. Then draw a similar set of curves for a Monod-Wyman-Changeux allosteric Uenzyme system. 

In our previous work [63], we studied the hydrolysis kinetics of lipase from Mucor javanicus in a modified Lewis cell (Fig. 4). Initial hydrolysis reaction rates (uri) were measured in the presence of lipase in the aqueous phase (borate buffer). Initial substrate (trilinolein) concentration (TLj) in the organic phase (octane) was between 0.05 and 8 mM. The presence of the interface with octane enhances hydrolysis [37]. Lineweaver-Burk plots of the kinetics curve (1/Uj.] = f( /TL)) gave straight lines, demonstrating that the hydrolysis reaction shows the expected kinetic behavior (Michaelis-Menten). Excess substrate results in reaction inhibition. Apparent parameters of the Michaelis equation were determined from the curve l/urj = f /TL) and substrate inhibition was determined from the curve 1/Uj.] =f(TL) ... 

The enzymatic activities of intercalated GOx-AM P layered nanocomposites at various pH values and temperatures were compared with the native enzyme in aqueous solution. In both cases, characteristic linear plots consistent with Michalis-Menton kinetics were obtained. The Lineweaver-Burk plots indicated that the reaction rates (Vmax) for free and intercalated GOx (3.3 and 4.0 pM min 1 respectively), were comparable, suggesting that the turnover rate at substrate saturation was only marginally influenced by entrapment between the re-assembled organoclay sheets. However, the dissociation constant (Km) associated with the activity of the enzyme was higher for intercalated GOx (6.63 mM) compared to native GOx (2.94 mM), suggesting... 

Characteristically, within certain concentration limits, if a chemical is absorbed by passive diffusion, then the concentration of toxicant in the gut and the rate of absorption are linearly related. However, if absorption is mediated by active transport, the relationship between concentration and rate of absorption conforms to Michaelis-Menten kinetics and a Lineweaver-Burk plot (i.e., reciprocal of rate of absorption plotted against reciprocal of concentration), which graphs as a straight line. 

The apparent kinetic constants were obtained from Lineweaver-Burk plots of AHH activities recorded in the presence of increasing concentrations of benzo(a)pyrene (0.001-1.0 mM). The plots were linear for both untreated and DBA-induced animals. The apparent V was 20- to 30-fold higher in hepatic microsomes from the induced skates whereas the apparent K values were of the same magnitude in control and treated fish. 

First, the activity of the enzyme was measured and kinetic parameters were determined by Lineweaver-Burk plots, using phenyhnalonic acid as the substrate. The results are summarized in Tabled. Among four mutants, C188S showed a drastic decrease in the activity (k -jt/Kn,). The low activity was due to a decrease in the catalytic tirrnover number (k(.jt) rather than in affinity for the substrate (Km). 

We examined the effect of restricted conformation on the activation entropy by kinetic studies at various temperatures [34]. Three kinds of substrates were subjected to the reaction phenylmalonic acid as the standard compound, ortho-chlorophenylmalonic acid as a substrate with an electron-withdrawing group, and indane-l,l-dicarboxylic acid as a conformationally restricted compound. The initial rates of the enzymatic decarboxylation reaction of three compounds were measured at several substrate concentrations at 15 °C, 25 °C, and 35 °C. The kcat and values at each temperature were obtained by a Lineweaver-Burk plot,... 

The main plots used in enzyme kinetics and receptor binding studies are the Scatchard plot, the Lineweaver-Burk plot, and the linearization for estimation of the Hill coefficient. This chapter gives a short survey of these transformations of enzyme kinetics or receptor binding data. 

Figure 8.4 The Lineweaver-Burk plot (A) and the Hanes plot (B) of typical enzyme kinetics in presence of a competitve (a) noncompetive (b), mixed type (c) and uncompetitive (d) inhibitor.

Figure 3.6 Evaluation of kinetic parameters in Michaelis-Menten equation (a) Lineweaver-Burk plot, (b) C /r versus plot, and (c) Eadie-Hofstee plot.

Bimolecular reactions of two molecules, A and B, to give two products, P and Q, are catalyzed by many enzymes. For some enzymes the substrates A and B bind into the active site in an ordered sequence while for others, bindingmay be iii a random order. The scheme shown here is described as random Bi Bi in a classification introduced by Cleland. Eighteen rate constants, some second order and some first order, describe the reversible system. Determination of these kinetic parameters is often accomplished using a series of double reciprocal plots (Lineweaver-Burk plots), such as those at the right. 

A Lineweaver-Burk plot of enzyme kinetics in the presence and absence of a noncompetitive inhibitor is shown in Figure E5.5. Umax in the presence of a noncompetitive inhibitor is decreased, but KM is unaffected. The effect of a competitive inhibitor on the direct linear plot is shown in Figure E5.6. 

Second, an enzyme assay may be used to measure the kinetic properties of an enzyme such as Ku, Vmax, and inhibition characteristics. In this situation, different experimental conditions must be used. If Ku for a substrate is desired, the assay conditions must be such that the measured initial rate is first order in substrate. To determine Ku of a substrate, constant amounts of enzyme are incubated with varying amounts of substrate. A Lineweaver-Burk plot (1/v vs. 1/[S]) or direct linear plot may be used to determine Ku and V. If a reaction involves two or more substrates, each must be evalu-... 

To determine KM values, conduct rate measurements (v) with at least four different concentrations of any given substrate, [S], and then analyze the data by any suitable kinetic plot such as the Lineweaver-Burke plot or the direct-linear plot (refer to any standard textbook of biochemistry for more information). 

Kinetic data obtained from linear Lineweaver-Burk plots. 

Figure 9 shows Lineweaver-Burk plots of dextrin hydrolysis rates in the presence of the block copolymer. Again, fairly good straight lines are obtained. Some other kinetical investigations also were made for the catalytic activity of the block copolymer, and similar tendencies of catalytic behavior were found compared with that of the random copolymer. 

Evaluate the Michaelis-Menten kinetic parameters by employing (a) the Langmuir plot, (b) the Lineweaver-Burk plot, (c) the Eadie-Hofstee plot, and (d) non-linear regression procedure. 

Mass transfer can alter the observed kinetic parameter of enzyme reactions. Hints of this are provided by non-linear Lineweaver-Burk plots (or other linearization methods), non-linear Arrhenius plots, or differing Ku values for native and immobilized enzymes. Different expressions have been developed for the description of apparent Michaelis constants under the influence of external mass transfer limitations by Homby (1968) [Eq. (5.69)], Kobayashi (1971), [Eq. (5.70)], and Schuler (1972) [Eq. (5.71)]. 

Lineweaver-Burk plot. None of the graphical procedures, however, yield reliable kinetic parameters, but are useful to obtain a qualitative feel for the kinetics of the system. 

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