A single enzyme's active site (the glowing pocket on the central sphere) binds nearby substrate molecules (orange) diffusing inside the transparent reaction vessel. Bound substrate is converted to product (green) and released. The instantaneous reaction velocity follows the Michaelis-Menten equation, driven by the current substrate count [S], the enzyme's maximum turnover rate Vmax, and its affinity constant Km.
v = Vmax * [S] / (Km_app + [S])
Km_app = Km * (1 + [I] / Ki) (competitive inhibitor)
Each frame, v (product molecules per second) is computed from this formula and used to convert the nearest diffusing substrate particle(s) into product at that exact rate — so the particle animation and the readouts are the same simulation, not two separate effects.
- [S]0 slider — sets how many substrate molecules start in the vessel.
- Km slider — lower Km means tighter enzyme-substrate binding, so velocity saturates at lower [S].
- Vmax slider — raises the enzyme's maximum turnover rate (more enzyme / faster catalysis).
- Inhibitor toggle — adds a fixed competitive inhibitor concentration that raises the apparent Km without changing Vmax, exactly as real competitive inhibitors do.
- Reset — restarts the reaction with the current slider settings.
This is the same kinetic law used to characterize real enzymes (e.g. hexokinase in glycolysis) and to design competitive-inhibitor drugs that slow a target reaction without altering its maximum rate.