Michaelis–Menten Kinetics
As enzyme-catalysed reactions are saturable, their rate of catalysis does
not show a linear response to increasing substrate. If the initial rate of
the reaction is measured over a range of substrate concentrations
(denoted as [S]), the initial reaction rate (v 0 ) increases as [S] increases,
as shown on the right. However, as [S] gets higher, the enzyme
becomes saturated with substrate and the initial rate reaches Vmax, the
enzyme's maximum rate.
The Michaelis–Menten kinetic model of a single-substrate
reaction is shown on the right.
There is an initial bimolecular reaction between the enzyme E and
substrate S to form the enzyme–substrate complex ES. The rate of
enzymatic reaction increases with the increase of the substrate
concentration up to a certain level called Vmax; at Vmax, increase in
substrate concentration does not cause any increase in reaction rate
as there is no more enzyme (E) available for reacting with substrate (S).
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