Eadie-Hofstee

Equation 11-18 is referred to as the Eadie-Hofstee equation, where V is plotted against v/C . However, both of these equations are sub-jeeted to large eiTors. Equation 11-18 in partieular eontains tlie measured variable v in both eoordinates, whieh is subjeeted to the largest errors. Eigures 11-2 and 11-3 show plots of Lineweaver-Burk and Eadie-Hofstee equations, respeetively. 

For the Eadie-Hofstee plot, both coordinates contain rates that are subjected to the greatest error, as indicated in Figure E.2.3. 

Eadie-Hofstee plot, 111 Electrode, 14, 15, 72, 73, 75-80 Electrodialysis, 351, 353-356, 393 Elemental composition, 228-230 Embden-Myerhof-Pamas pathway (EMP), 3, 207, 244-251... 

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. 

If instead we use the Eadie-Hofstee transformation, Equation 17.2 becomes... 

Figure 17.2 Enzyme Kinetics Results from the Eadie-Hofstee...

The Scatchard plot is bound free (/i/ L, y-axis) vs. bound (B, x-axis) (the Eadie-Hofstee plot is bound vs. bound/free). If this equation is applicable (i.e., the binding represents a simple bimolecular... 

Traditionally, data corresponding to (4) are analysed by using a Lineweaver-Burk approach, but an Eadie-Hofstee treatment is preferable for statistical reasons (Dowd and Riggs, 1965 VanEtten et al., 1967a Bender and Komiyama, 1978). With the present, widespread availability of... 

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. 

More accurate means of determining Km and Vmax are offered by either the Lineweaver-Burke (double reciprocal) plot or the Eadie-Hofstee plot (Figure 2.7). 

Figure 2.7 (a) Lineweaver-Burke plot (b) Eadie-Hofstee plot... 

Use the data in Table 2.2 to plot Michaelis-Menten, Lineweaver-Burke and Eadie-Hofstee graphs to determine Km and Vm DC values. Answers are given at the end of the chapter. 

Test your IT skills. Try creating Excel spreadsheets based on the Michaelis-Menten equation (Equation 2.9) and its variants (Equations 2.10 and 2.11). Insert into your spreadsheets your own values for JCm, Vmax, [S], [I] and A) and use Excel to plot Michaelis-Menten, Lineweaver-Burke and Eadie-Hofstee graphs. 

Historically, data have been transformed to facilitate plotting on linear plots such as Lineweaver-Burk (1/y versus 1/[S]), Hanes-Woolf ([S]/y versus [S]), or Eadie-Hofstee (v/[S] versus y). However, with the present availability of affordable nonlinear regression and graphing software packages such as GraphPad Prism,... 

Purification. One main peak was observed with detection at 405 nm, when purified lignin peroxidase was analyzed by Mono Q chromatography. The retention time of the main peak was 11.8 min and its area was 98.9% of the total peak area. Possibly the enzyme solution contains, however, two isoenzymes which have very similar properties. The Kj of the purified lignin peroxidase for veratryl alcohol was 139 on the basis of Eadie-Hofstee plot. 

In addition to the Lineweaver-Burk plot (see p.92), the Eadie-Hofstee plot is also commonly used. In this case, the velocity v is plotted against v /[A]. In this type of plot, Vmax corresponds to the intersection of the approximation lines with the v axis, while Km is derived from the gradient of the lines. Competitive and non-competitive inhibitors are also easily distinguishable in the Eadie-Hofstee plot. As mentioned earlier, competitive inhibitors only influence Km, and not Vmax- The lines obtained in the absence and presence of an inhibitor therefore intersect on the ordinate. Non-competitive inhibitors produce lines that have the same slope (llower level. Another type of inhibitor, not shown here, in which Vmax and lselective binding of the inhibitor to the EA complex. 

Allosteric enzymes shift the target enzyme s saturation curve to the left (see p. 92). In Eadie-Hofstee and Lineweaver-Burk plots (see p. 92), allosteric enzymes are recognizable because they produce curved lines (not shown). 

See Double-Reciprocal Plot Hanes Plot Direct Linear Plot Dixon Plot Dixon-Webb Plot Eadie-Hofstee Plot Substrate Concentration Range Frieden Protocol Fromm Protocol Point-of-Convergence Method Dal-ziel Phi Relationships Scatchard Plots Hill Plots... 

DALZIEL PHI RELATIONSHIPS DIRECT LINEAR RLOT DIXON RLOT DIXON-WEBB RLOT DOUBLE-RECIRROCAL RLOT EADIE-HOFSTEE RLOT FRIEDEN RROTOCOL FROMM RROTOCOL HANES RLOT HILL RLOT... 

Pirrang, Liu, and Morehead [22] have elegandy demonstrated the application of saturation kinetics (Michaehs-Menten) to the rhodium(II)-mediated insertion reactions of a-diazo /9-keto esters and a-diazo /9-diketones. Their method used the Eadie-Hofstee plot of reaction velocity (v) versus v/[S] to give and K, the equilibrium constants for the catalytic process. However, they were unable to measure the Michaelis constant (fC ) for the insertion reactions of a-diazo esters because they proved to be too rapid. 

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