My Easy Science
Enzyme Kinetics Plotter
Plot the Michaelis-Menten curve, the Lineweaver-Burk double reciprocal, and the Eadie-Hofstee plot. Add an inhibitor and watch Vmax and Km move.
Michaelis-Menten: rate against substrate
Lineweaver-Burk: 1/rate against 1/substrate
Eadie-Hofstee: rate against rate/substrate
Set Vmax and Km, then tap Draw the plots.
For learning only. Not for patient care decisions. Always check with a qualified professional and the product label.
Lineweaver-Burk values
| Value | No inhibitor | With inhibitor |
|---|---|---|
| Slope (Km/Vmax) | — | — |
| y-intercept (1/Vmax) | — | — |
| x-intercept (−1/Km) | — | — |
| Vmax′ (µmol/min) | — | — |
| Km′ (mM) | — | — |
Competitive lines meet on the y-axis, non-competitive lines meet on the x-axis, and uncompetitive lines are parallel.
Rate data
| [S] (mM) | v, no inhibitor (µmol/min) | v, with inhibitor (µmol/min) |
|---|
Values from the drawn curves.
Starting values
Worked example: Vmax 100, Km 5, no inhibitor — v = 50 at [S] 5 mM and 80 at [S] 20 mM. Lineweaver-Burk intercept 0.01, slope 0.05.
How it works
Checked against hand-worked examples (see the page source comments).
Results are shown to 2 decimal places.
An enzyme speeds up a reaction by binding its substrate, and the rate follows the Michaelis-Menten equation: v = Vmax × [S] / (Km + [S]). Vmax is the fastest the enzyme can go, when every active site is full. Km is the substrate concentration at half of Vmax, and it measures how tightly the enzyme holds its substrate: a small Km means tight binding.
Inhibitors change Vmax and Km in a pattern that tells you how they work. A competitive inhibitor competes for the active site, so it raises the apparent Km but leaves Vmax alone: add enough substrate and you can outrun it. A non-competitive inhibitor binds elsewhere and lowers Vmax without touching Km. An uncompetitive inhibitor only binds the enzyme-substrate complex, so it lowers both Vmax and Km. The Lineweaver-Burk plot makes the pattern easy to read: competitive lines meet on the y-axis, non-competitive lines meet on the x-axis, and uncompetitive lines are parallel.