3D Michaelis-Menten Kinetics Simulation

Initial rate30.0 µM/s

Vmax60.0 µM/s

Occupancy50%

Product0.0 µM

From molecular collisions to Vmax and Km

Kinetics assay

Mission: increase substrate and discover why reaction rate approaches a maximum instead of rising forever.

Experiment

Substrate concentration, [S]40 µM

Enzyme concentration, [E]1.0 µM

Km40 µM

Competitive inhibitor, [I]0 µM

Simulation speed1×

Live measurements

Initial rate, v₀30.0 µM/s

Vmax60.0 µM/s

Site occupancy50%

Product formed0.0 µM

At [S] = Km, half of the maximum rate is reached. Half the enzyme sites are occupied on average.

Michaelis-Menten curve

Current curveNo inhibitor◆ Current measurement

Microscope & camera

Focus: noneTap a structure

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Tap an enzyme, substrate, active site, enzyme–substrate complex, product, or inhibitor for a compact microscopic view. Drag empty space to pan.

Teacher / Demo tools

Interactive kinetics lecture

The lesson starts immediately. Each narrated point changes the molecules, arrows, graph, and microscopic view before the next point begins.

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Ready for Michaelis-Menten kinetics

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Learning objectives

Connect molecular binding cycles to a measured initial reaction rate.
Explain why the curve approaches Vmax.
Interpret Km as the substrate concentration at half Vmax.
Predict how enzyme amount and competitive inhibitor change the curve.
Use the graph to estimate kinetic parameters.

Key concepts

For a simple one-substrate enzyme, v₀ = Vmax × [S] ÷ (Km + [S]). Vmax equals kcat × [E]. This is an educational idealization of initial-rate measurements; molecule sizes, time, and concentrations are conceptually scaled.

Suggested experiments

Set [S] far below Km and double [S]. Compare the rate.
Set [S] equal to Km and verify that v₀ is half Vmax.
Raise [S] far above Km and look for saturation.
Double enzyme concentration and compare Vmax.
Add inhibitor and see whether high [S] can restore the original Vmax.

Questions for exploration

Why do extra substrate molecules wait when every active site is busy?
How is Km different from maximum rate?
Why does a competitive inhibitor shift the curve right?

Applications and misconceptions

Michaelis-Menten analysis supports drug development, clinical enzyme tests, fermentation, and metabolic engineering. Km is not a reaction rate, and saturation does not mean the reaction stops. Competitive inhibition raises apparent Km but does not lower the ideal Vmax.

Kinetics challenge

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