100
µmol/min
5
mM
-0.2
1/mM
20
µmol/(min·mM)
100
µmol/min
5
mM
-0.2
1/mM
20
µmol/(min·mM)
The Lineweaver-Burk Calculator derives the kinetic parameters Vmax and Km from the double-reciprocal plot of enzyme kinetics data. The Lineweaver-Burk transformation converts the hyperbolic Michaelis-Menten equation into a linear form by plotting 1/v against 1/[S], making it straightforward to extract kinetic parameters from the slope and y-intercept.
This linearization method has been historically important in enzymology for determining kinetic constants and analyzing inhibition patterns. Enter the slope and y-intercept obtained from your double-reciprocal plot to calculate the fundamental kinetic parameters of your enzyme.
The Lineweaver-Burk equation is the reciprocal form of the Michaelis-Menten equation:
1/v = (Km/Vmax) × (1/[S]) + 1/Vmax
This is a linear equation (y = mx + b) where:
Slope = Km / Vmax
Y-intercept = 1 / Vmax → Vmax = 1 / Y-intercept
Km = Slope × Vmax = Slope / Y-intercept
X-intercept = -1 / Km
Inputs
Results
From the double-reciprocal plot, a slope of 0.05 and y-intercept of 0.01 yield Vmax = 100 µmol/min and Km = 5 mM, consistent with a moderately efficient enzyme.
Inputs
Results
A small slope relative to the y-intercept indicates a low Km (0.1 mM), meaning the enzyme has very high affinity for its substrate and reaches half-maximal velocity at a low concentration.
Despite distorting error distribution and giving disproportionate weight to low-substrate data points, the plot remains widely used because it provides clear visual identification of inhibition types. Competitive, uncompetitive, and mixed inhibition each produce distinctive patterns of intersecting lines that are easy to interpret.
The double-reciprocal transformation magnifies errors in measurements at low substrate concentrations, which are taken at the highest 1/[S] values and have the greatest influence on the line. Modern practice favors direct nonlinear fitting of the Michaelis-Menten equation, which provides more statistically reliable parameter estimates.
Measure initial reaction velocities at several substrate concentrations. Plot 1/v versus 1/[S]. Fit a straight line through the data points using linear regression. The slope and y-intercept of this line are the values you enter into this calculator to derive Vmax and Km.
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