Enzyme Activity

Dial up temperature, pH, substrate, and enzyme concentration and watch reaction rate rise and fall — matches the school experiment on how temperature and pH affect enzymes, with a real Michaelis-Menten curve and a reaction-progress colour change.

Still frame from the Enzyme Activity simulation
Free to run with an account

What you can adjust

Enzyme
0 – 2

Picks the enzyme's illustrative Km and optimum pH (every preset shares the same ~37 °C optimum temperature — ordinary body temperature). Amylase and catalase work best near neutral pH; pepsin works best in the strongly acidic stomach.

Substrate concentration
0 – 50 mM

Concentration of the substrate the enzyme is acting on. At low concentration the rate rises roughly in proportion to this; once it is well above the enzyme's Km, adding more barely speeds the reaction up further (the enzyme is saturated).

Enzyme concentration
0.1 – 2 x

Relative amount of enzyme present (1.0x is a standard amount). The maximum possible rate (Vmax) scales directly with this — twice the enzyme, twice the top speed of the reaction.

Temperature
0 – 80 °C

Reaction temperature. Activity rises with temperature up to the enzyme's optimum, then falls sharply above it as the enzyme denatures and permanently loses its shape. Marked as a highlight point on the traced curve.

pH
1 – 14

Reaction pH. Activity peaks at the enzyme's own optimum pH and falls off on both sides as the enzyme's shape (and its active site) is disrupted.