Michaelis-Menten Equation Calculator

Michaelis – Menten Equation Calculator

Calculate the initial reaction rate for a one-substrate enzyme reaction and see how close the enzyme is to its limiting rate.

Rate: 40.000 µM/s Saturation: 40.00% Regime: below Km

Reaction inputs

Michaelis constant (Km)

µM

Positive concentration at which the rate equals half of Vmax.

Max reaction speed (Vmax)

µM/s

Positive limiting rate for the chosen enzyme concentration.

Substrate concentration [S][S][S][S][S][S][S][S][S][S][S][S][S][S][S][S][S][S]) and explains the roles of the two kinetic parameters.

Practical cautions

Use consistent units and assay conditions. Temperature, pH, ionic strength, enzyme concentration, cofactors, inhibitors, and substrate depletion can all change observed kinetics. Vmax normally changes with total enzyme concentration, while Km may shift when the mechanism or assay environment changes. For parameter estimation from measured substrate – velocity pairs, nonlinear regression is generally preferable to relying on a transformed plot; the GraphPad Michaelis – Menten model guide describes direct nonlinear fitting.