Enzyme Activity Simulator
Change substrate, temperature, pH and inhibitors and watch the reaction rate of an enzyme.
Drag the orange dot on the rate graph to change the substrate amount, or use the sliders. Watch the enzymes catch substrates.
About the Enzyme Activity Simulator
Free enzyme simulator. Adjust substrate concentration, enzyme amount, temperature, pH and inhibitors, watch enzymes catch substrates and see the Michaelis-Menten rate graph. Built for biology, the enzyme activity simulator runs instantly in your browser: change a setting or drag an object and the result updates at once, so you learn by trying things out rather than only reading about them.
Change substrate, temperature, pH and inhibitors and watch the reaction rate of an enzyme. Use it to explore biology ideas at your own pace, then check what you found against the key ideas further down this page.
How to use the Enzyme Activity Simulator
- Use the controls to change Substrate, Enzyme amount, Temperature, pH, Inhibitor. The simulation reacts instantly.
- Pick an option such as None, Competitive, Non-competitive to switch modes or load an example.
- Press "Reset products" to start, reset or change what is happening.
- Where you see a glowing handle, object, weight or atom, drag it with your mouse or finger. Everything responds in real time.
- Watch the readouts and graphs update as you experiment, and compare what you see with the key ideas below.
Things to try
- Raise the temperature past 45 °C.
- Add a competitive inhibitor, then raise substrate.
- Move the pH away from 7.
- Watch the rate graph flatten at high substrate.
Key ideas you can learn
- Reaction rate rises with substrate until all enzymes are busy (saturation).
- Each enzyme has an optimum temperature and pH; too hot denatures it.
- A competitive inhibitor raises Km. A non-competitive inhibitor lowers Vmax.
Where this is used in the real world
Enzymes are used in washing powders, brewing, cheese making, medicine and diagnostic tests. Many drugs work by inhibiting an enzyme.
Who is this simulation for?
Biology students and teachers who want to explore living systems, populations and genetics interactively and safely.
For teachers: project it on the board, let students predict what will happen, then run it together. For students: change one thing at a time and write down what changes.
Frequently asked questions
Why do enzymes stop working at high temperature?
Heat changes the shape of the enzyme (it denatures), so the substrate no longer fits the active site.
What is an enzyme inhibitor?
A molecule that slows an enzyme. A competitive inhibitor competes with the substrate for the active site.
Is the Enzyme Activity Simulator free to use?
Yes. It is completely free, with no signup, no download and no ads inside the simulation. It runs in your web browser.
Does the Enzyme Activity Simulator work on a phone or tablet?
Yes. It uses touch as well as the mouse, so you can drag objects with your finger. A larger screen makes the controls easier to see.