- Eadie-Hofstee diagram
In
biochemistry , an Eadie-Hofstee diagram (also Woolf-Eadie-Augustinsson-Hofstee or Eadie-Augustinsson plot) is a graphical representation ofenzyme kinetics in whichreaction velocity is plotted as a function of the velocity vs. substrateconcentration ratio::
where v represents reaction velocity, Km is the
Michaelis-Menten constant , [S] is the substrate concentration, and Vmax is the maximum reaction velocity.It can be derived from the Michaelis-Menten equation as follows:
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invert and multiply with :
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Rearrange:
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Isolate v:
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A plot of v vs v/ [S] will yield "Vmax" at the intercept with the Y-axis and the slope is -"Km" . Like other techniques that linearize the
Michaelis-Menten equation , the Eadie-Hofstee plot was used historically for rapid identification of important kinetic terms like "Km" and "Vmax", but has been superseded bynonlinear regression methods that are significantly more accurate and no longer computationally inaccessible. It is also more robust against error-prone data than theLineweaver–Burk plot , particularly because it gives equal weight to data points in any range of substrate concentration or reaction velocity. (The Lineweaver–Burk plot unevenly weights such points.) Both plots remain useful as a means to present data graphically.One drawback from the Eadie-Hofstee approach is that neither
ordinate norabscissa representindependent variable s: both are dependent on reaction velocity. Thus any experimental error will be present in both axes. Furthermore, the typical measure of goodness of fit, the correlation coefficient "R", is not applicable.ee also
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Michaelis-Menten equation
*Lineweaver–Burk plot
*Hanes-Woolf plot References
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