7 Enzyme Activities 163by preparing a series of substrate concentrations
evenly spaced along the 1/[S] axis, that is, diluting
the stock solution of substrate by two-, three-, four-,
five-,... fold (Copeland 2000).
Eadie-Hofstee Plots
The Michaelis-Menten equation can be rearranged
to give vKm(v/[S]) Vmaxby first multiplying
both sides by Km[S], and then dividing both sides
by [S]. The plot will give a linear curve with a slope
of Kmand a yintercept of vwhen vis plotted
against v/[S] (Fig. 7.4). The Eadie-Hofstee plot has
the advantage of decompressing data at high sub-
strate concentrations and being more accurate than
the Lineweaver-Burk plot, but the values of vagainst
[S] are more difficult to determine (Eadie 1942,
Hofstee 1959). It also has the advantage of observ-
ing the range of vfrom zero to Vmaxand is the most
effective plot for revealing deviations from the hy-
perbolic reaction when two or more components,
each of which follows the Michaelis-Menten equa-
tion, although errors in vaffect both coordinates
(Cornish-Bowden 1996).Hanes-Wolff PlotsThe Lineweaver-Burk equation can be rearranged
by multiplying both sides by [S]. This gives a linear
plot [S]/v(1/Vmax) [S] Km/Vmax, with a slope of
1/Vmax, the yintercept of Km/Vmax, and the xinter-
cept of Kmwhen [S]/vis plotted as a function of
[S] (Fig. 7.5). The plot is useful in obtaining kinetic
values without distorting the data (Hanes 1932).Eisenthal-Cornish-Bowden Plots (the Direct
Linear Plots)As in the Michaelis-Menten plot, pairs of rate values
of vand the negative substrate concentrations [S] are
applied along the y and x axis, respectively. Each
pair of values is a linear curve that connects two
points of values and extrapolates to pass the inter-
section. The location (x, y) of the point of intersec-
tion on the two-dimensional plot represents Kmand
Vmax, respectively (Fig. 7.6). The direct linear plotsFigure 7.3.The Lineweaver-Burk double-reciprocal
plot.
Figure 7.4.The Eadie-Hofstee plot. Figure 7.5The Hanes-Wolff plot.