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Lineweaver-Burk Calculator

Linearized enzyme kinetics.

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Overview

The Lineweaver-Burk equation is a linear transformation of the Michaelis-Menten equation achieved by taking the reciprocal of both sides. This double-reciprocal plot allows biochemists to easily determine the maximum reaction velocity (Vmax) and the Michaelis constant (Km) by fitting experimental data to a straight line.

Symbols

Variables

y = 1/v, m = Gradient (Km/Vmax), x = 1/[S], c = Y-intercept (1/Vmax)

1/v
s/u
Gradient (Km/Vmax)
1/[S]
1/mM
Y-intercept (1/Vmax)
s/u

Apply it well

When To Use

When to use: Apply this equation when you need to calculate kinetic parameters from experimental reaction rates at varying substrate concentrations. It is particularly useful for identifying the mechanism of enzyme inhibition, such as distinguishing between competitive and non-competitive inhibitors based on changes in the intercept and slope.

Why it matters: This linear model simplifies the analysis of enzyme kinetics, which is vital for drug discovery and understanding metabolic pathways. It allows for the visual diagnosis of how a molecule affects an enzyme's affinity and catalytic power, facilitating the development of therapeutic inhibitors.

Avoid these traps

Common Mistakes

  • Plotting v instead of 1/v.
  • Forgetting the y-intercept term.

One free problem

Practice Problem

Given an enzyme-catalyzed reaction where the slope of the Lineweaver-Burk plot (m) is 0.5 min and the y-intercept (c) is 0.2 min/µmol, calculate the reciprocal velocity (y) when the reciprocal of the substrate concentration (x) is 4 L/µmol.

Gradient (Km/Vmax)0.5 s
1/[S]4 1/mM
Y-intercept (1/Vmax)0.2 s/u

Solve for:

Hint: Use the linear form y = mx + c to find the total reciprocal velocity.

The full worked solution stays in the interactive walkthrough.

References

Sources

  1. IUPAC Gold Book: Michaelis constant, Km
  2. IUPAC Gold Book: Maximum velocity, Vmax
  3. Lehninger Principles of Biochemistry, 7th Edition, Nelson, D.L. and Cox, M.M.
  4. Wikipedia: Lineweaver-Burk plot
  5. Lehninger Principles of Biochemistry, 7th Edition, by Nelson and Cox
  6. Berg, Tymoczko, and Stryer Biochemistry
  7. Nelson and Cox Lehninger Principles of Biochemistry
  8. Atkins Physical Chemistry