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Enzyme Exploration

Animation speed
Test in progress — leaving resets it

① Find the fit

An enzyme is a protein that speeds up one reaction. Only the right substrate fits its active site. Pick the shape that matches. (This is the simple lock-and-key picture. You will see a better one in step ②.)

Matched: 0 / 4
Pick a substrate to try

② Build the reaction

Enzyme to build with
Step palette · tap a step, or drag it into a numbered slot
Your timeline
Energy diagram · the dot follows your animation

Kinetics: what controls the rate?

Each substrate that bumps into an active site facing the right way can be converted to product. Change the sliders and watch the molecules, the counters, and the graph react together.

Choose an enzyme
⚠ DENATURED — this sample is permanently damaged. Cooling it will not fix it. Press “Fresh sample”.
Temperature 37°C
pH 6.8
Substrate amount 50
Enzyme amount 4
Reaction chamber (live)
0products formed
0.0live rate (products / s)
—rate on the graph (% of standard)
0%active sites occupied
Michaelis–Menten curve: rate vs. substrate
Activity vs. temperature
Activity vs. pH

Denaturation: watch a protein fall apart

Denaturation unfolds an enzyme so its active site loses its shape. Run the slow ramp and watch for the cliff. Then try cooling it back down.

Choose an enzyme
Temperature 37°C
pH 6.8
Slow ramps
⚠ DENATURED — cooling or fixing the pH will not refold this protein. Only a fresh sample works.
The enzyme chain (live)
Native vs. this sample
Activity as you heat and then cool

Inhibition & cofactors

Other molecules can block an enzyme, switch it on, or complete it. Pick a mechanism. The molecules above and the graph below change together.

Graph: