ABSTRACT
Perhaps the simplest scheme for describing a biochemical reaction catalyzed by a single enzyme E is the irreversible conversion of a substrate S to a product P
through the reversible formation of an intermediate enzyme-substrate complexES. If the kinetics obey the Michaelis-Menten model, the reaction rate V is related to concentration by
V= dCs _ dCP _ VmaxCs dt - dt - Km + Cs (75)
where V max is the maximum possible chemical reaction rate. The Michaelis-Menten constant Km is related to the three equilibrium constants by
and is also defined as the concentration where the reaction rate is reduced to half of the maximum rate. One International Unit (1 U) of the enzyme is
64 ENZYME-BASED ELECTROCHEMICAL BIOSENSORS
defined as the amount that catalyzes 1 JLM of the product per minute at a specified temperature and pH or for other relevant factors at a reference state.
